Steel fiber reinforced concrete (SFRC) offers improved toughness, crack resistance, and impact resistance. Nano-silica enhances the strength, durability, and workability of concrete. This study investigated the combined effect of nano-silica and steel microfibers, termed micro-concrete reinforced with steel fibers embedding nano-silica (MRFAIN), on the mechanical properties of concrete. The aim was to determine the influence of different percentages of nano-silica and steel microfibers on fresh state properties, mechanical strength, and mechanical performance of MRFAIN. MRFAIN mixtures were prepared with cement, sand, water, superplasticizer, varying dosages of nano-silica (0–2%), and steel microfibers (0–2% by volume). Mechanical properties evaluated at 28 days included compressive strength, flexural strength, modulus of elasticity, and fracture energy. Incorporating steel microfibers reduced workability but enhanced mechanical properties like strength and ductility. Nano-silica addition showed variable effects on compressive strength but increased tensile strength. Optimal nano-silica content was 1% and steel microfibers 2%, giving compressive strength 122.5 MPa, tensile strength 25.4 MPa, modulus of elasticity 42.7 GPa. Using nano-silica and steel, microfibers enhanced the mechanical performance of steel fiber-reinforced concrete. This shows potential for reducing construction waste and pollution. Further research can optimize the proportions of nano-silica and steel microfibers in MRFAIN. It primarily comprises cement, water, and aggregates such as sand and gravel. Concrete’s versatility, affordability, and structural capabilities allow it to be used for various applications in buildings, infrastructure, and construction projects. Concrete’s properties and performance characteristics are critical for determining its suitability and ensuring concrete structures’ durability, load-bearing capacity, and service life. Key properties that influence the quality and usefulness of concrete include strength, stiffness, durability, shrinkage, creep, permeability, and thermal properties. Extensive research has been conducted to understand further the factors affecting concrete properties and develop innovative concrete mixtures and materials. Standards and codes provide specifications and guidelines for concrete to ensure quality control during construction. However, variability in concrete constituents, curing conditions, and testing methods pose challenges. Ongoing advances in concrete technology aim to optimize properties and performance to expand concrete’s sustainable implementation in structural engineering3. Workability refers to the ease of mixing, placing, and finishing concrete, which is essential for achieving concrete’s desired consistency and quality. Shrinkage refers to the reduction in the volume of concrete due to drying and curing, which can cause cracking and other problems if not properly managed4. In addition to these properties, concrete can also be evaluated based on its thermal properties, sound insulation properties, and fire resistance, among others. The properties of concrete are influenced by several factors, including the composition of the concrete mixture, the curing conditions, the environment, and the loading and exposure conditions5.Some critical properties of concrete include strength, durability, workability, and shrinkage. Strength refers to the ability of concrete to resist forces and load, which is crucial for the stability and safety of structures. Durability refers to the ability of concrete to resist various environmental factors, such as weathering, chemical attacks, and physical impacts, and to maintain its strength and function over timeRecent studies have shown that adding nano-silica can enhance the properties of conventional concrete by improving workability, reducing bleeding, and increasing strength and durability. However, excessive nano-silica may lead to high viscosity and delay in setting time. On the other hand, steel fiber reinforced concrete (SFRC) enhances toughness, ductility, and energy absorption capacity, making it suitable for applications involving high strength and dynamic loads. Nevertheless, SFRC also suffers from issues like difficulties in mixing, increased viscosity when fresh, and potential long-term corrosion problems in aggressive environments. Therefore, an optimal approach is needed to incorporate nano-silica into SFRC to maximize the advantages while overcoming the limitations of both materials  can regulate the temperature of concrete structures and reduce energy consumption13. Finally, there has also been progress in using advanced technologies, such as sensors and monitoring systems, to optimize the curing and maintenance of concrete structures. These technologies can provide real-time data on the properties of concrete, allowing for more effective and efficient management of concrete structures over their lifespan14. These developments in the field of concrete properties demonstrate the ongoing efforts to improve the quality, performance, and sustainability of concrete structures. Concrete has several advantages that make it a widely used construction material. One of its key advantages is its strength, which allows concrete to resist forces and load, providing stability and safety to structures. Concrete is also known for its durability. It can withstand environmental factors, such as weathering, chemical attacks, and physical impacts, and maintain its strength and function over time. Some studied the effects of adding granite polishing waste as paste and aggregate replacements on the packing densities and performance of concrete mixes15. They found optimal replacement levels for maximizing packing density and strength while reducing cement content. Researchers investigated ternary blending of cement with metakaolin and silica fume to improve binder paste’s packing density and properties16. Adding metakaolin and silica fume increased packing density, released excess water, and improved fresh and hardened properties. The roles of particle packing and water coating thickness on the carbonation and strength of γ-dicalcium silicate-based materials were examined17. They identified a critical carbonation depth and optimal water coating thickness for maximum strength and CO2 uptake. Some studied the combined use of γ-dicalcium silicate and slag for improved carbonation resistance of blended materials. Adding γ-dicalcium silicate to slag blends enhanced CO2 sequestration, pore refinement, and surface hardening, with an optimal combination for minimizing carbonation depth18. Others proposed a volume-based approach to concrete mixture design for improved accuracy and consistency19. They discussed measuring packing density and controlling water/slurry film thickness as a basis for linking fresh properties to hardened performance. Some quantified the effect of varying cementitious paste volume at a constant water–cement ratio on the properties of concrete20. Reducing paste volume increased density and strength but decreased workability, which could be compensated by adding superplasticizers or fillers. Researchers developed infilled cementitious composites featuring high sustainability and performance21. He optimized fiber-aggregate skeleton packing and ultra-high performance concrete infill to reduce cost/CO2 while enhancing strength. Others applied volume-based design to develop ultra-low cement concrete mixtures22. Concurrent paste replacement and sand proportioning methods allowed for minimizing cement while maximizing performance. Optimal paste volume and sand content were identified. Researchers revealed the roles of packing density and slurry film thickness in the synergistic effects of adding metakaolin and silica fume23. Increased packing density and proper slurry film thickness explained synergistic flowability, strength, and durability improvements. Others studied the effect of rigid steel fibers on aggregate packing density. Fibers caused proportional packing density reduction dependent on volume and aspect ratio24. Others studied the effect of rigid steel fibers on aggregate packing density. Fibers caused proportional packing density reduction dependent on volume and aspect ratio. Larger fibers and smaller aggregates showed greater packing disruption. Using finite element analysis, Ref.25 developed an improved pullout test method for rebar in plain/fiber concrete. Inserting a rubber pad and PTFE film reduced testing errors from uneven contact pressure and friction. Others proposed a new bond model for rebar in steel fiber-reinforced concrete26. They modified the Model Code 2010 to incorporate fiber effects and finite initial stiffness for realistic bond-slip analysis. Researchers studied the co-addition of metakaolin and silica fume in mortar. Metakaolin improved workability, and silica fume reduced it, but their combination mitigated negative effects while synergistically enhancing strength27. Others used wet packing method to measure packing densities of cement-pulverized fuel ash-micro silica ternary systems28. Limitations of the Andreasen and Andersen model were revealed through comparison. Researchers recycled waste glass powder by substituting paste volume in UHPFRC, maintaining composition29. Optimal glass powder enhanced workability, strength, and microstructure while permitting cement content reduction. Others optimized recycled aggregate proportioning in concrete blocks to increase packing density and match natural aggregate performance without increasing cement30. Packing-based prediction equations were derived. Some developed a new direct tension test method for fiber-reinforced concrete using dumbbell specimens. Analysis showed reduced stress concentrations. Fiber effects on first-cracking and post-cracking behavior were quantified. Some extended the water film thickness concept to seawater cement paste31. At similar film thickness and superplasticizer, seawater decreased workability but slightly increased strength compared to freshwater paste. Reference32 modeled the combined effects of water film thickness and fiber factor on the workability of polypropylene fiber reinforced mortar. This revealed the dominant roles of water film thickness and fiber factor. Reference33 studied the effects of different fiber materials and volumes on fiber-reinforced concrete's strength and fracture properties.Another area of improvement has been using nanomaterials and other advanced additives in concrete, which can enhance its properties and improve its performance under various loading and exposure conditions34. One of the central themes of this review is the challenges associated with concrete properties, such as the inherent variability in concrete mixtures, the impact of environmental conditions, and the absence of standardized testing methods35. On the flip side, this survey also underscores the significant progress being made in the field of concrete properties. This encompasses the development of novel and enhanced concrete mixtures employing alternative binders, incorporating nanomaterials and advanced additives, and utilizing cutting-edge technologies like sensors and monitoring systems to optimize the curing and maintenance of concrete structures36. Concrete stands out as a construction material for its numerous merits, including strength, durability, versatility, affordability, and fire resistance. Nonetheless, further research is imperative to fine-tune concrete properties, ensuring concrete structures’ quality, performance, and safety. The core aim of the study was to scrutinize the impact of adding fibers and nanoparticles on the mechanical attributes of concrete. The investigation assessed compressive and flexural strength, tensile strength, modulus of elasticity, and failure patterns in concrete with varied fiber and nanoparticle dosages. The ultimate objective was to pinpoint the optimal dosage of fibers and nanoparticles that would augment the mechanical properties of concrete, thus contributing to the development of more resilient construction materials. Integrating Nano-Silica in concrete has diverse effects on its fresh and hardened properties, including enhanced workability, reduced bleeding, and improved mechanical characteristics37. Nevertheless, it’s worth noting that excessive nano-silica can result in increased viscosity and extended setting time, presenting handling challenges. While bolstering several properties, steel fiber-reinforced concrete (SFRC) has constraints, such as potential non-uniform distribution, increased viscosity, and corrosion concerns in harsh environments. This study delves into the mechanical attributes of concrete mixtures with varied compositions and fiber reinforcements38. It’s divided into two phases: Phase 1 evaluates compressive strength, flexural strength, and modulus of elasticity with diverse additives, while Phase 2 explores the effects of increasing fiber dosage on multiple mechanical properties and fracture energy. This research employs standardized testing methods and specimen types. It ultimately compares outcomes across different mixtures, seeking to provide valuable insights into the application of fiber-reinforced concrete in structural engineering.This literature review comprehensively examines concrete properties and their associated evaluation techniques. Many factors influence concrete characteristics, including composition, curing conditions, environmental variables, and loading and exposure conditionsAs mentioned, the benefits of incorporating nanoparticles and steel fibers into composite materials are evident, among which the high energy absorption capacity, significant gains in tensile strength and increased ductility, and compressive strength and compactness stand out. However, the choice of the % of addition of fibers to be included in the mixture should be reasonable and follow the mechanical properties of the fibers and matrix. This chapter presents the description and characterization of the constituent materials of MRFAIN, as well as the methodology of their composition. The preparation, curing, and testing of specimens are also described. This study aims to obtain the mechanical characterization of a composition of the high-strength concrete matrix that is considered suitable for self-compacting concretes and for which the following tests were performed: compressive strength test, and tensile strength test (bending). A more complete characterization was made of specimens with the mixture of reference already studied. In addition to the tests already mentioned, the following was the determination of fracture energy modulus of elasticity test. With this set of tests, it is possible to characterize the behavior of this type of concrete that the trials in this phase of the study were carried out for 28 days of age concrete. It should be noted that the complementary tests were performed in the mixtures whose results presented the lowest deviations and more coherent values with the desired performances. For the study of the mixtures, the concrete matrix was considered, consisting of the respective mortar matrix  and fine sand, adding the nanoparticles and fibres to the reference mixtures previously characterized.Preliminary tests were first conducted on mortar mixtures with different combinations of cement and supplementary cementitious materials (SCMs) including silica fume, metakaolin, and limestone powder (mixtures A–E). Based on workability, compressive strength, and drying shrinkage results, mixture D with 10% metakaolin and 5% silica fume was identified as the optimal SCM blend. Mixture A with 100% cement was also selected as a benchmark for comparison. The hooked-end steel fibers were sourced from multiple suppliers. Since the mechanical properties can vary depending on manufacturing processes, the ranges reported reflect the typical values provided by the suppliers rather than measured data.3, the amounts of all other mix components in the micro-concrete matrix were multiplied by 0.7 to determine their quantities for the concrete-containing aggregates. To ensure uniform dispersion, the nano-silica particles were dispersed in the mixing water using ultrasonication for 15 min before mixing. Proper dispersion of nanoparticles was verified by scanning electron microscopy imaging of the concrete microstructure.To optimize the nano-silica content for particle packing density enhancement, a range of nano-silica replacement levels from 1 to 5% of cement weight were evaluated. The particle size distribution of the cement, silica sand, fibers, and nano-silica were measured by laser diffraction analysis. Packing density modeling was then performed to determine the nano-silica dosage required to fill the voids between the larger particles. The mix proportions were developed based on a modified absolute volume method. For a target coarse aggregate content of 300 L/m3. This grade of cement allows concretes with higher resistances than the more current cement. The additions aim to improve the characteristics and performance of the specified concrete. In this sense, H.D. smoke silicas (volume mass of 2.2 kg/dm3), Comital limestone filer (volume mass of 2.7 kg/dm3), f-type fly ash (mass volume of 2.3 kg/dm3), and Sibelco silica flour (volume mass of 2.6 kg/dm3) and Silica flour from Sibelco (volume mass of 2.6 kg/dm3). The choice of smoke silicas and fly ash was based on the desired performance increase for concrete. These polyzoan additions increase mechanical strength and better durability, provided that an adequate cure is performed. The use of lime filer and silica flour was due to the objective of considering the increase in the volume of ligating powder without increasing the desired cement act, which has the function of the filer by filling the voids, and the second has a reactivity effect on the cement matrix.Due to cement’s importance in concrete, your choice must follow the desired resistance performance. The cement chosen for this work was the CEM I 52.5 R with a volume mass of 3.12 kg/dm3), is utilized. Figure The usual normal density aggregates in concrete production are usually of granite or limestone origin. Its classification depends on the granulometry of the material and is divided into fine aggregates in the case of sand and coarse aggregates for gravel. Despite the influence of sand granulometry on the properties of mortars and concrete, particularly in compactness and workability, it was decided to use only fine sand to produce microconcrete. Consequently, of MRFAIN, the normal density aggregates used are usually thin. The studied matrix can constitute the resistant binder fraction and any self-compacting mixture; moreover, it is the fine aggregates that mainly influence the workability and the need for water and additives, the compactness, and the air content, so the behavior can then be extrapolated to concrete with coarse aggregates of the equivalent matrix. In the present work, only one type of aggregate of normal age, fine sand 0/1 mm  used was produced based on oxides, with a minimum purity of 99.5%. Its density (kg/dm3), obtained in the experimental characterization, was 2.22.In this investigation it was initially intended to study the improvements caused by the incorporation of various nanomaterials in the performance of concrete. However, given the rapid development of the Nano-concrete Project, in which this study was conducted more comprehensively regarding mechanical performance and durability, the influence of only the addition of nano-SiOThe diameter of the silica particles was measured using Transmission Electron Microscopy (TEM), is 104 nm, with a first standard deviation of 9 nm as shown in Fig. Ethical approval for experiments was obtained from the appropriate institutional review board or equivalent ethics committee, ensuring adherence to ethical guidelines and standards throughout the research.3, the proportions of the micro concrete matrix will be multiplied by 0.7 to obtain the equivalents in concrete with the same matrix and with coarse aggregates. The study was, therefore, based on a dosage of binder (cement and additions) for self-compacting concrete, a value that varies between 550 and 600 kg/m3.The methodology used in the composition of the MRFAIN was based on the philosophy of the composition method. However, since we collaborated only with the binder matrix that contains the fine sand, the granulometric adjustment part of the reference curves is not applied. Thus, the composition study was based on the definition and respective parameters of the binding fraction, as well as the expression of absolute volumes, to control the unitary volume of the mixture. It is also referred to that, considering a fraction of coarse aggregates of around 300 lt/m3, adopting a W/L ratio (water/binder) of 0.3; and target air contents of 2.5% to 3% in the mortar matrix.Based on what was mentioned above, self-compacting micro concrete mixtures were studied and produced in the laboratory, with a cement dosage of 800 kg/mIn each series, five reference mixtures were produced, one with cement (Ci) and the rest with cement and additions: mixture A, with Ci only; mixture C, with Ci and addition of 7% Silica Fume (S.F.); mixture D, with Ci and addition of 20% fly ash (CV); mixture B.C. with Ci and additions of 7% S.F. and 20% Filler (F); mix D.E. with Ci and additions of 7% Silica Flour (F.S.) and 20% CV. As mentioned, the dosage of superplasticizer was adjusted in such a way as to maintain constant, in each series, the workability, measured by the fluidity obtained in the spreading test, and the air content, with the final adjustment of the mixture being conducted in the dosage of sand.Mixtures A and D were later considered for adding fibers, representing the mixture with cement alone and the mixture with the addition that showed the best performance in preliminary tests. In mixtures A and D, steel microfibers were then added, in volume percentages of 0.5% (5.82), 1% (1.82), 2% (2.82), and 3% (3.82), to analyze the behavior and performance of the mixtures. Based on the results obtained in preliminary tests, it was decided to study only with 1% and 2% of fibers. Then, the study of the mixtures with the addition of the mentioned nanoparticles (nano-silica) was developed, referenced as mixture S, being the addition by replacing the cement, in dosages of 1% and 2%, equally without and with the steel microfibers.In this experimental procedure, two types of curing were also studied, the normal curing subject to the same type of special curing.The simplified designation for the mixtures was based on the cement dosage (8) and a certain W/C ratio (2), thus obtaining the base mixture (0.82). The remaining simplified designations of each mixture reflect the variation of the abovementioned parameters, summarized in Table 39.The quantification of the aggregates is conducted after knowing the absolute volume of the binder paste. The absolute volume of the aggregate mixture is determined based on the absolute volume Eq. .1\documeentclass1pt{minimaThe prediction of the mechanical resistance of the MRFAIN matrix was determined through the Feret expression as a function of age, considering a correction of the matrix resistance of the binder paste. The calculation of the predicted mechanical resistance consists of estimating the resistance of the binding paste, fc,j, through the Feret expression given in Eq. , where K3 of cement, without the addition of fibers and nanoparticles, with a predicted density of 2273 kg/m3, assigning it the designation of A0.82. That said, different parameters were varied: types of additions, volumetric dosages of fibers, and volumetric dosages of nanoparticles. In this way, the designations were obtained according to the variations introduced.The choice of characterized mixtures during phase 1, was based on the study of a reference MRFAIN, with 800 kg/m40.Table 41. The results of the characterization of nano-silica revealed its chemical composition and physical properties. Chemical analysis showed that nano-silica consists mainly of silicon dioxide (SiO2) with a high purity of over 99%. Trace amounts of Aluminium, iron, and calcium impurities were also detected. The physical properties of Nano-Silica included its significantly reduced particle size, ranging from a few nanometres to tens of nanometres. It exhibited a high specific surface area exceeding 100 m2/g, attributed to its small particle size and high surface activity. The morphology of Nano-Silica varied, with particles displaying spherical, rod-like, or amorphous structures. The density was approximately 2.2 g/cm3, similar to conventional silica fume. Additionally, Nano-Silica particles may possess a surface charge, influencing their dispersion and interaction with other particles in a liquid or solid matrix. These characterization results provide valuable insights into the chemical and physical nature of Nano-Silica, enabling its effective utilization in various applications.Table The experimental plan followed in this study aimed to obtain the mechanical characterization of a composition of high-strength concrete matrix suitable for self-compacting concrete. The addition of nanoparticles and steel fibers into composite materials has shown evident benefits, including high energy absorption capacity, significant gains in tensile strength, increased ductility, compressive strength, and compactness. The choice of the % of fibers to be included in the mixture was informed and followed the mechanical properties of the fibers and matrix. The constituent materials of MRFAIN were described and characterized, and the methodology of their composition was presented. The preparation, curing, and testing of specimens were also represented. The tests performed included compressive strength test, tensile strength test (bending), determination of fracture energy, and modulus of elasticity test. The trials were carried out for 28 days of concrete age, and the methodology is shown in Fig. 3. The additions included H.D. smoke silicas, Comital limestone filer, f-type fly ash, Sibelco silica flour, and Silica flour from Sibelco. The choice of smoke silicas and fly ash was based on the desired performance increase for concrete. These polyzoan additions increase mechanical strength and better durability, provided that an adequate cure is performed. The use of lime filer and silica flour was due to the objective of considering the increase in the volume of ligating powder without increasing the desired cement act, which has the function of the filer, by filling the voids, and the second has a reactivity effect on the cement matrix42.For the study of the mixtures, the concrete matrix was considered, consisting of the respective mortar matrix  and fine sand, adding nanoparticles and fibers to the reference mixtures previously characterized. The cement chosen for this work was the CEM I 52.5 R, with a volume mass of 3.12 kg/dm3) was used for the aggregates. The studied matrix can constitute the resistant binder fraction and any self-compacting mixture. Moreover, the fine aggregates mainly influence the workability and the need for water and additives, the compactness, and the air content, so the behavior can then be extrapolated to concrete with coarse aggregates of the equivalent matrix.Only one type of aggregate of normal age, fine sand 0/1 mm of The Guia Argilis  used was produced by synthesis by Smart Innovation, based on oxides, with a minimum purity of 99.5%. Its density (kg/dm3), obtained in the experimental characterization, was 2.22. The methodology used in the composition of MRFAIN was based on the philosophy of the composition method. However, the details of the methods used were not provided.This investigation addressed the influence of only the addition of nano-SiO2, which allows the compression to be applied to each specimen until it fractures. The corresponding compressive strength, fcm, is calculated from the specimens’ average breaking strength. In the specimens from Phase 2, the compression test was carried out in a 3000 kN hydraulic press as in Fig. In Phase 1 mixtures, the specimens used for this test were the halves resulting from the bending test, with 3 specimens tested at 7 days and 6 specimens at 28 days per mixture. The test is also carried out in the press, using the device with compression plates of 50 × 50 mmcm, was obtained from the arithmetic mean of the number of specimens. The result obtained is the ratio between the maximum breaking strength and the cross-sectional area of the specimen. The bending test on the prismatic specimens of the Phase 1 mixture was carried out in a universal press, using a 3-point test device, until failure was reached. The flexural strength results, fcf, were obtained through the average of three specimens tested at 28 days. For the specimens of Phase 2 mixtures, the bending flexural strength, fcf, was obtained through bending rupture tests and characterized following the NP EN 12390-5 standard. The tests were carried out at 28 days, and the strength was determined for the specimen from the flexion test (cross-section 100 × 100 mm2) and the sample from the fracture energy test (cross-section 100 × 66.7 mm2). The bending test involves applying a concentrated load at mid-span and along the smallest dimension of the specimen, which is supported by the two central thirds of the span as in Fig. The average compressive strength value, f3. The standard gives that the concrete behaves linearly elastic when subjected to small strains or stresses within a certain range43. This assumption is because the elastic modulus of concrete is relatively constant within this range and can be used to accurately predict the deformation and behavior of the material under various loading conditions. The test is based on applying cyclic load on the specimen, between the lower and upper limits, to measure the deformation the sample reaches in each loading and unloading cycle. The loading and unloading speed of the specimens was 0.5 MPa/s. The deformation readings were performed between the two reading points, duly glued to each of the two opposite faces of the sample, as in Fig. The static modulus of elasticity was determined according to the specification for prismatic specimens of 100 × 100 × 400 mmThe modulus of elasticity can also be determined in flexion, using the results obtained during the flexion test. During the test, it is possible to decide on the displacement as a function of the applied force, resulting in a graph of the type as in Fig. 3, at 28 days of age. The standard specifies the test conditions and procedures for conducting the freeze–thaw test, including the number of cycles, the temperature range, and the methods for measuring and recording the mass loss of the specimens. The standard also guides the preparation and handling of the specimens and the interpretation and reporting of the test results. This flexural tensile test involves applying a point load at mid-span and measuring the displacements. The specimens were placed on rollers, allowing the beam support points to rotate. The fracture energy is obtained based on the work, W0, performed by the beam during loading. As the failure was intended to occur at mid-span, a notch (100 × 20 × 33 mm3) was made in each specimen, per the recommendation above. The test was conducted with deformation control, with the control measure corresponding to the maximum deflection suffered by the beam at mid-span, as in Fig. The fracture energy test was performed according to the RILEM recommendation in prismatic specimens of 100 × 100 × 50 mmcm, at 28 days, as given in Table As expected, the diameters between 20 and 25 cm were obtained for mixtures with dosages of up to 2% metallic fibers. The expected results regarding the air content were obtained, with slight deviations since the superplasticizer was adjusted to minimize these deviations. The density obtained was initially expected, with close results. As mentioned, the mechanical properties were characterized in the hardened state: compressive and tensile strength, modulus of elasticity, and fracture energy. In Phase 1 mixtures, the specimens used for this test were the halves resulting from the bending test. From the average breaking strength of the specimens, the corresponding compressive strength was obtained, fcm at 28 days, as given in Table For the Phase 2 mixes, after conducting the test on the three specimens, the following results were obtained for compressive strength, fThere was an increase in compressive strength in all mixtures with the increase in fiber dosage, which was very noticeable in most situations. In the test specimens, the presence of fibers alters the type of failure, prolonging the test, with a reduced load increase but with a failure that does not generate the detachment of the lateral faces of unconfined concrete. The existing fibers along the fracture lines prevent lateral concrete detachment and show a different failure pattern than the fibreless concrete, as shown in Fig. 3) was carried out in a universal press, using a 3-point test device, until failure was reached. Flexural strength results, fcf at 28 days, obtained for Phase 1 mixtures are shown in Table As mentioned, the bending test on the prismatic specimens of the Phase 1 mixtures  evaluating the influence of fibers and nanoparticles on concrete, (ii) study correlations between the properties and parameters studied in the MRFAIN; (iii) comparing experimental results with the codes47. There is a known loss of workability for dosages of 3% of fibers, with the same introduction of fibers affecting fluidity, largely due to their influence on the massing process. The steel fibers exhibited a wide range of tensile strength and elastic modulus values, highlighting the need for tighter specifications on fiber mechanical properties in order to reduce variability in the composite performance.The flow test was used to evaluate the fluidity, where the spreading diameter represents a parameter of the fluidity of the mixtures. Figure 48. Adding fibres also increases the modulus of elasticity; concerning the effect of fibers on fracture energy, although the fibers cause a notorious increase, this study is not conclusive of the direct relationship with the dosage of fibers. The test specimens with the presence of fibers changed the type of fracture/breakage; once the maximum load was reached, there was a greater deformation and no total detachment of concrete compared to the concrete without fibers. With the increase in the % of fibers, the rupture mode was increasingly dubious, and a cutting surface was developed accompanied by a deformation49. The most notorious differences occurred in concretes with a high % of fibers, which significantly increased their properties in the hardened state and fluidity losses in properties in the fresh state. As expected, the additions and type of cure showed some improvements in the properties of concrete, but the small size of the sampling does not allow the exact of this influence. From the analysis of the results obtained in the MRFAIN trials, it was found that the addition of fibers and the increase in their dosage resulted in a significant increase in compressive strength. In the test specimens, the presence of the fibers altered the type of fracture/breakage, with increased ductility, once the maximum load was reached, there was a greater deformation and without total detachment of concrete, compared to the concrete without fibers. The increase in resistance was more notorious for concrete with 3% fiber (high %)50. The following Figures show the evolution of compressive strength, fcm, depending on the type of cure and the different rates of fibers and nanoparticles used in the concrete under study. In Fig. In the hardened state, mechanical properties were characterized by compressive and tensile strengths, modulus of elasticity, and fracture energy. The analysis of the results obtained in the MRFAIN assays found that adding fibers and increasing their dosage increased compressive and tensile strengthFigure 51.Figure Figure 52. The analysis of the results obtained in the MRFAIN trials found that adding fibers and increasing their dosage increased tensile strength. In the test specimens, the presence of the fibers altered the type of fracture/breakage; once the maximum load was reached, there was a more significant deformation and no total detachment of concrete compared to fibreless concrete53. The following Figures show the evolution of tensile strength, fcf, depending on the cure type and the different percentages of fibers and nanoparticles used in the concrete under study. Figure Figure 54.Figure Figure 55. Figure Figure elasticity, E, was affected by adding fibers in concrete, demonstrating a slight influence of metal fibers on the specimens and their stiffness by the confinement capacity of the matrix, as shown in Fig. 56.The modulus of 57.From the analysis of the experimental results related to the characterization of the properties of MRFAIN, it was possible to observe the advantage of the incorporation of steel fibers in concretes, both in terms of resistance and ductility; however, unlike some studies already published, the influence of nanoparticles has not proved so notorious and some aspects as conclusive. These results show the already known tendency of the difficulty of generalization of the tests with nanoparticles, given their properties and variation of the reactivity itself in the ligating matrix, by the differences in raw material and the production process of synthesisTable The optimized nano-silica SFRC mixture with 2% nano-silica exhibited reduced bleeding and segregation and a minor viscosity increase compared to the control SFRC. This demonstrated the positive effects of the nano-silica in enhancing particle packing density. The increased packing density refined the pore structure, significantly reducing permeability while maintaining workability. The addition of 2% nano-silica also provided a 12% increase in the 28-day compressive strength. The strength enhancement can be attributed to the nano-silica providing additional sites for forming strength-contributing calcium-silicate-hydrate gel. Thus, the study results aligned with the theory that optimized nano-silica content designed based on particle packing modeling can improve the fresh and hardened properties of SFRC.Incorporating steel microfibers at higher volume fractions of 1–2% enhanced concrete’s compressive strength, tensile strength, flexural strength, and fracture energy. However, excessive fiber content above 2% led to reduced workability.The addition of nano-silica showed variable effects on compressive strength, with an optimal 1% cement replacement dosage. However, nano-silica consistently improved the tensile strength of concrete.The combined use of microfibers and nano-silica demonstrated the best mechanical performance, with 2% steel fibers and 1% nano-silica leading to peak improvements in compressive strength (122.5 MPa), tensile strength (25.4 MPa), and modulus of elasticity (42.7 GPa).Steel fibers altered the failure mode of concrete by increasing ductility, energy absorption, and post-cracking resistance compared to plain concrete.The results showcase the potential of microfibers and nanomaterials to enhance the mechanical properties of concrete. Further research can optimize the proportions and types of micro and nanoscale reinforcements.This experimental study provided significant insights into the effects of steel microfibers and nano-silica additions on the mechanical properties of concrete. The key conclusions are:The strategic use of steel microfibers and nano-silica integration can lead to stronger, tougher, and more durable concrete, enabling wider implementation in structural and construction applications.Supplementary Information.


Delayed antibiotic prescriptions with instructions to wait a defined period of time before filling the prescription is a strategy often used to decrease the unnecessary use of an antibiotic. Although "watchful waiting" for illnesses, such as acute otitis media (AOM) and pharyngitis, that are suspected of being viral is recommended, little is known about how often delayed antibiotics are prescribed at our institution. The primary objectives of this study were to characterize delayed prescriptions for pediatric patients with AOM or pharyngitis and to assess each prescription for adherence to guidelines.Design: This study was a retrospective chart review. Pediatric patients with AOM and pharyngitis assessed and discharged from the Emergency Department (ED) between March 1, 2019 to February 28, 2021 were considered for inclusion. Data were collected from the ED Treatment Record by a trained research assistant.Setting: Our study was completed in a pediatric ED at a tertiary hospital in Canada.Exposures or interventions: Patients prescribed a delayed antibiotic on discharge from the ED.Main Outcome Measures: Frequency of delayed antibiotic prescribing, proportion of antibiotic prescriptions adherent to guidelines for empiric choice, dose, and duration. Adherence to guidelines was assessed using local guidelines and position statements by the Canadian Pediatric Society as the gold standards.Statistical analysis: Data were entered in REDCap and exported to excel for descriptive analysis.Delayed antibiotics were prescribed to 21.2% (332/1563) of patient encounters during the study period. Amoxicillin was the most commonly prescribed antibiotic . The majority of delayed prescriptions were prescribed for AOM . Most patients  received a delayed prescription for an empiric antibiotic that adhered to guidelines. Fewer prescriptions adhered to guidelines for dose  and duration .Most patients received the appropriate empiric antibiotic to treat AOM and pharyngitis however, dose and duration of use may be improved through antimicrobial stewardship initiatives.Emily Black, BSc(Pharm), PharmD, Drug Evaluation Alliance of Nova Scotia: Grant/Research Support|Research Nova Scotia: Grant/Research Support


In 2020 to 2021, oral antibiotics were most prescribed for skin (37.7%), genitourinary (20.2%), and respiratory conditions (10.8%). Antibiotic use in the “Access” group (WHO AWaRe classification) improved from 85.6% (2018) to 92.1% (2021). Areas of improvement included a lack of documentation of reasons for antibiotic use, as well as inappropriate antibiotic prescription for skin conditions. Conclusion: There was a marked reduction in antibiotic prescriptions associated with the onset of the COVID-19 pandemic. Further studies could address the gaps identified here and evaluate private-sector primary care to inform antibiotic guidelines and the local development of stewardship programs.Background: Antibiotic prescription practices in primary care in Singapore have received little scholarly attention. In this study, we ascertained prescription prevalence and identified care gaps and predisposing factors. Methods: A retrospective study was conducted on adults (>21 years old) at six public primary care clinics in Singapore. Prescriptions >14 days were excluded. Descriptive statistics were used to showcase the prevalence data. We used chi-square and logistic regression analyses to identify the factors affecting care gaps. Results: A total of 141,944 (4.33%) oral and 108,357 (3.31%) topical antibiotics were prescribed for 3,278,562 visits from 2018 to 2021. There was a significant reduction in prescriptions ( Antimicrobial resistance is widely recognized as a global public health threat . No new Singapore launched its National Strategic Action Plan on Antimicrobial Resistance in 2017 in response to the Global Action Plan for antimicrobial resistance developed by the World Health Assembly . This leDuring the COVID-19 pandemic, changes in patients’ behavior in terms of seeking healthcare and physicians’ prescription patterns may have affected community antibiotic prescription rates . SeveralIn our study, we aim to examine the current patterns of antibiotic prescriptions for adults in primary care, as well as to identify potential care gaps for improvement, and factors influencing these gaps. We hope that this will pave the way for the development of local antibiotic guidelines within primary care and improve governance and stewardship in the post COVID-19 era, toward the creation of a Healthier Singapore.A retrospective observational study was conducted using data extracted from electronic health records (CPSS2 and EPIC) of patients from 6 public primary care clinics  in Singapore, from 2018 to 2021. This included April 2020, which was the peak of the COVID-19 pandemic in Singapore . De-idenVariables included patient demographics, visit diagnoses, presence of chronic diseases, such as diabetes mellitus and chronic kidney disease, antibiotic name and class, and prescriber information, such as place of practice, number of years of practice, training location, and family physician’s accreditation status. Visit diagnoses in clinics were coded using the International Classification of Disease (ICD-10). Institution level data on the total number of visits for each visit diagnosis were also collected to determine the antibiotic prescription rate for each condition. For the purposes of this study, each antibiotic prescribed equates to 1 antibiotic prescription, regardless of number of visits. To analyze antibiotic prescription by diagnoses, visits prescribed with oral antibiotics were grouped into categories based on the indicated diagnosis. These categories consisted of respiratory, skin, genitourinary, gastrointestinal, infectious disease, and dental conditions. Prescriptions for miscellaneous or chronic disease diagnoses where indications were unable to ascertain were listed as ‘Undefined’. The diagnosis categorization was conducted independently by two family physicians based on the World Health Organization (WHO) International Classification of Diseases 10th revision (ICD-10) , and splOften, there were oral antibiotics prescribed for visits with multiple diagnoses. We coded a tiered ranking logic system  to selecFor visits prescribed with topical antibiotics that were incongruent with the coded diagnosis, we reclassified the diagnosis such that they were prescribed for their indicated conditions and route . In the case of topical ciprofloxacin, which can be used as an eye or ear drop, we differentiated them by the prescribed dosage, duration, and route of application.Data from 1 clinic were analyzed for the prescription rate of oral antibiotics, but was excluded from other analyses as the clinic was newly built and lacked data before 2021. All antibiotics prescribed by dentists were assumed to be for dental conditions. To ensure data validity and accuracy of ranking classification, 100 case notes were randomly selected and extracted for audits. All information was true and corresponded to the diagnoses and antibiotic characteristics that were extracted. This also ensured and validated the accuracy and robustness of the tiered ranking logic system in diagnosis selection, topical antibiotic diagnosis reclassification, and ciprofloxacin eye and ear drop dichotomization.p-value of <0.05 in the two-sided test was considered statistically significant. Descriptive statistics were performed, and numerical variables were represented as mean with standard deviations, or n (%) for categorical variables. Antibiotic prescription rate was derived by dividing the number of prescriptions over the total number of patient visits. Segmented regression analysis was performed to describe antibiotic prescription trends before and after the peak of the pandemic. Chi-square tests were used for categorical variables  while logistic regression was performed for continuous variables  to analyze antibiotic prescription for undefined conditions, “Watch” group antibiotic prescriptions, topical antibiotic prescriptions with irrelevant diagnoses, and dual antibiotic prescriptions for skin and soft tissue conditions. Subsequently, combined multivariate logistic regression was performed, considering all variables collected on the gaps identified.Rstudio (R version 4.2.0), IBM SPSS Statistics Version 29.0 and Microsoft Excel 2010 were used in data cleaning and analysis. The research was conducted in accordance with the Declaration of Helsinki national and institutional standards and approved by the NHG Domain-Specific Review Board (DSRB) on June 2022 (2022/00319). p < 0.01) before and after the peak of the COVID-19 pandemic in Singapore in April 2020 , skin and soft tissue conditions (28.9%), and genitourinary conditions (15.2%) . In 2021p < 0.001), presence of diabetes mellitus  and chronic kidney disease , place of practice (p < 0.001), and having an accredited family physician  were significantly associated with antibiotic prescriptions for undefined conditions  conditions remained stable from 2018 to 2021 . While tnditions .The changes in antibiotic prescription habits observed in 2020 and 2021 prompted us to assess the factors contributing to the prescription of Watch group antibiotics. This is showcased in Topical antibiotic prescriptions were highest in the younger age groups (age 22–44), with gradual increments of ENT (0.463% to 0.59%) and skin (1.69% to 1.90%) topical antibiotic prescription rates from 2018 to 2021. This is described in Topical antibiotics prescribed without s relevant diagnoses increased most significantly for skin conditions, where the number of prescriptions for non-skin-related diagnoses increased from 5122 (35.2%) in 2018 to 5934 (40.1%) in 2021 . PatientA significant percentage (35.8%) of same-visit prescriptions of oral and topical antibiotics for skin conditions was also observed compared to oral antibiotic prescriptions. Younger patient ages  and higher years of experience of the physician  were associated with dual antibiotic prescriptions . In the This observational study is one of the first conducted on oral and topical antibiotic use within primary care clinics in Singapore, showcasing the prevalence of prescription practices and revealing the care gaps. All prescription data were included as they were extracted from a health records database, with no missing data. Diagnoses were mapped to prescription data, with prescription rates calculated based on the overall patient visits, which showcased the actual burden of antibiotic use. Some physician and patient factors affecting antibiotic prescription were also included and analyzed, with meaningful and applicable results. However, this was not an exhaustive list; future studies should focus on this area to help build a more complete picture.The antibiotic prescription rate reduced with age, which was likely due to a higher proportion of older patients attending for chronic disease visits compared to younger patients. This could also be due to poorer knowledge associated with younger patients in Singapore, leading to more presentations and antibiotic requests . NotablyData from 2021 also showed that skin and genitourinary conditions accounted for the majority (57.9%) of total oral antibiotic prescriptions, highlighting shifts in antibiotic prescription habits among physicians and patient’s antibiotic requests. The high percentage of antibiotic prescriptions for dental conditions could be attributed to our algorithm for diagnosis classification . FurtherWithin the clinics, the lack of prioritization in terms of ensuring the accurate coding of diagnosis for antibiotic prescriptions made the assessment and determination of the indications for antibiotic prescriptions challenging. This was evident in the two gaps that we identified: the increase in oral antibiotics prescribed for chronic condition diagnoses and topical skin antibiotic prescriptions with non-skin diagnoses. Similar gaps were discovered in the USA; the antibiotic prescribed was not listed as a diagnostic code in over 50% of cases . We postWhile the increase in the “Access” group’s antibiotic prescriptions was due to reduced clarithromycin use in respiratory conditions, the “Watch” group’s antibiotic utility remained high in genitourinary and gastrointestinal conditions. As we discovered that more experienced, locally trained family physicians were more likely to prescribe “Watch” group antibiotics, this could stem from previous outdated local antimicrobial guidelines, in terms of encouraging ciprofloxacin use for urinary tract infections . This loOur study discovered an increasing use of dual oral and topical antibiotics for skin conditions, despite discouragement from international guidelines and studies due to a possible increased risk of antimicrobial resistance . The facA potential limitation in this study is selection bias (due to the use of one public primary care cluster in Singapore), which may not be representative of the whole primary care landscape. Our study found that oral antibiotics were prescribed in 3–5% of all patient visits; this was likely an under-estimate, given that a result of 10% was reported in the USA . StudiesThis study showcases the prevalence of antibiotic prescriptions within public primary care in Singapore and their significant reduction, particularly for respiratory conditions during the COVID-19 pandemic. The gaps identified include inaccurate diagnosis coding for oral and topical antibiotic prescriptions, and dual antibiotic use for skin and soft tissue infections. These are associated with certain patient and physician factors. While the usage of “Watch” group antibiotics has decreased, greater emphasis can be placed on antibiotics prescribed for certain diagnoses. This paves the way for further studies in primary care in Singapore and lays the foundation for updated antimicrobial guidelines and stewardship programs in primary care in Singapore.


N = 1598) in the pre-AMS period to 78.0% (N = 841) in the post-AMS period (p < 0.001). The consumption of ceftriaxone significantly decreased, while the use of cefazolin increased more than nine times. No severe adverse reactions or increases in surgical site infections were detected after the intervention. The implementation of an AMS in the surgical ward demonstrated a trend towards a positive overall impact on the selection and duration of prophylactic antibiotics for surgery, with positive results also observed in other variables associated with the prescription of these antibiotics.This study aims to characterize the impact of the implementation of an antimicrobial stewardship program (AMS) on the optimal selection of surgical antibiotic prophylaxis in adult patients. This is a retrospective quasi-experimental study that compared the selection and duration of antibiotics for all surgical prophylaxis prescriptions over six months, both before (pre-AMS) and after a five-year intervention of AMS (post-AMS). In addition, data related to the consumption of antibiotics, adverse drug reactions, and surgical site infections throughout the years of the intervention were analyzed. The rate of appropriate selection of antibiotic prophylaxis in surgical procedures improved to 80% during the post-AMS period. The percentage of optimal duration increased from 69.1% ( Antibiotics represent one of the most significant contributions to public health, as they prevent and treat life-threatening infectious diseases. However, their excessive and indiscriminate use has led to several problems, including an alarming increase in antibiotic resistance, a reduction in the availability of effective antibiotics against multi-resistant pathogens, and a rise in healthcare costs ,2.K. pneumoniae ranged from 10% to 69% across various countries in this region [The Latin American Network for Antimicrobial Resistance Surveillance (ReLAVRA) has reported a sustained increase in antimicrobial resistance over the last decade. This increase exhibits wide heterogeneity in its magnitude; for example, resistance to meropenem in s region ,4.Surgical wards represent a critical area where the use of antimicrobials must be optimized. Around 14–17% of healthcare-associated infections worldwide consist of surgical site infections, and surgical antibiotic prophylaxis reduces the risk across different procedures . ApproxiClostridioides difficile (CD) infection [Regarding the duration of prophylaxis, it is generally recommended that surgical antibiotic prophylaxis should be initiated within 1 h before incision and discontinued within 24 h postoperatively for most procedures . Conversnfection .Antimicrobial stewardship programs (AMSs) represent a strategy with favorable results in optimizing the use of antibiotics. The implementation of AMSs in Latin America has been challenging due to several obstacles ,13. ThesDue to an upward trend in the use of broad-spectrum antibiotics, the clinical administration of the Hospital Clínica Bíblica (HCB) approved the implementation of AMS in June 2015. This initiative was proposed by the Department of Pharmacy, led by the hospital clinical pharmacist, and supported by other healthcare professionals, such as an infectious disease physician, a clinical microbiologist who specializes in bacteriology, and the nurse who oversees the Infection Control Committee. The AMS model chosen for implementation by the hospital does not impose restrictions on antimicrobial prescription. A handshake stewardship methodology was used, in which a change in prescription habits is sought through daily prescription monitoring, education, and direct communication with physicians [The AMS’s first project on this topic was in gynaecological surgery, which achieved positive results. A similar approach was continued for the rest of the group of surgical specialties in a progressive five-year program . The strThe objective of this study is to evaluate the effects of implementing an AMS on the prescription of surgical antibiotic prophylaxis for surgeries conducted at HCB, located in San José, Costa Rica. Additionally, this research aims to compare other variables related to the five-year intervention period, including consumption patterns of frequently used preoperative antibiotics and patient safety outcomes.p < 0.001) from 20% (N = 325) to 80% (N = 671). Additionally, the percentage of optimal treatment duration also demonstrated a significant increase (p < 0.001), rising from 69% (N = 1104) to 78% (N = 656).Following a five-year intervention with an AMS, we observed a marked improvement in the appropriate selection of drugs for surgical prophylaxis, with the optimal rate rising significantly  out of 1598 procedures conducted. In the post-AMS period, out of the 841 procedures conducted, 191 (22.71%) were administered antibiotics for more than 24 h. This change represents a significant improvement in the duration of the prophylaxis. Cesarean deliveries, orthopedic procedures, and hysterectomies represent the prescriptions where improvements were significant .Ceftriaxone was the most frequently used antibiotic during the pre-AMS period, and its usage underwent a reduction of 60.5% in the post-AMS period. On the other hand, the most used antibiotic during the post-AMS period was Cefazolin. The current study demonstrates that the implementation of AMS may have resulted in a significant shift in prescription patterns, as evidenced by improvements in both the selection and duration of surgical antibiotic prophylaxis.In Latin American hospitals, compliance with the clinical guidelines for antibiotic prophylaxis, as determined by point prevalence surveys, has shown room for improvement, with an adherence rate of approximately 44.3% (ranging from 28.5% to 54%). This is mainly characterized by issues in the selection and duration of antibiotics . The datCesarean deliveries and orthopedic surgeries are the procedures most frequently performed at our hospital. Notably, there has been a significant improvement in the selection and duration of antibiotic prophylaxis for these surgeries. Numerous studies from various regions across the globe have documented positive results in terms of prophylactic drug selection for gynecologic, obstetric, and orthopedic procedures after implementing an AMS in medical centers. These outcomes include cost reduction, enhancements in antibiotic prescription practices, and tangible clinical benefits for patients ,25,26,27Our results indicate no improvement in the appropriate use of antibiotics for head and neck surgeries. In this type of surgery, it is necessary to carry out an additional intervention with the otolaryngologists, following the same intervention approach as with other specialties. These physicians are prescribing surgical prophylaxis in clean procedures that do not routinely require antibiotics, such as septoplasty, functional endoscopic sinus surgery (FESS), thyroidectomy, and tonsillectomy. Furthermore, they are extending the use of antibiotics, which has not been shown to provide benefits to patients . AdditioThe study found an optimal discontinuation rate of 78% for antibiotics. While a significant improvement was made, additional efforts are necessary to reduce the use of antibiotics even further in urologic, plastic surgery, and other procedures performed in this center. It is still a common practice among many surgeons to continue prophylactic intravenous or oral antibiotics for more than 24 h after the procedure. However, it is well documented that this practice does not affect subsequent surgical site infections and could increase the incidence of adverse effects . In the In our pursuit of altering prescription patterns, our primary objective is to ensure the long-term sustainability of these changes while also fostering a deep conviction among physicians regarding the positive impact of these changes on patient wellbeing.At HCB, our AMS program employs a strategy known as handshake stewardship, a strategy that has proven successful in other programs. Through this approach, we give prescribers a sense of ownership, effectively minimizing potential resistance from physicians. Simultaneously, this strategy has the potential to influence pharmacological management by making specialists aware that their prescription practices are being monitored and evaluated on an ongoing basis ,31,32,33Prior to the implementation of the AMS, Ceftriaxone was commonly used as the antibiotic of choice for many surgeries. This same pattern has been demonstrated in other Latin American countries . While tE. coli [Cumulative reports of antibiotic sensitivity were conducted at the HCB during the periods 2014–2015 and 2016–2017, which coincide with the development of our study. Significant decreases in ESBLs were observed among E. coli . It is lE. coli . The anaE. coli .The hospital has achieved a low incidence of surgical site infections, which is attributed to various factors, including the appropriate use of antibiotics. The use of antibiotics is a well-established practice supported by strong evidence for preventing the occurrence of infections . This inEnsuring the successful adoption of AMS is paramount in tackling the escalating issue of antibiotic resistance within the region. Strengthening AMS in Latin America entails pivotal steps, including allocating additional resources and gaining a comprehensive understanding of the substantial challenges at hand. This endeavor encompasses evaluating the safety culture and acknowledging the human factors that exert influence on antibiotic prescribing practices . By straIt is crucial to finely adjust the implemented interventions from the perspective of continuous quality improvement. Initially, this AMS directed education toward surgeons of various specialties. However, in numerous instances, anesthesiologists at this facility are responsible for prescribing prophylactics. Consequently, based on recommendations from the surgeons themselves, the scope was expanded to include these specialists. Additionally, as part of the conducted group educational sessions, the educational coverage was extended to encompass internists and intensivist physicians due to their pivotal role , in prescribing prophylactic antibiotics after conducting preoperative assessments on hospitalized patients, particularly those at high risk. These adjustments were pivotal in achieving the objectives of this AMS, underscoring the effectiveness of the continuous quality improvement approach in redefining effective actions .Due to the time-intensive nature of conducting audits as performed in this specific study, we unfortunately lack quarterly results showcasing the incremental improvements in adherence to the clinical guidelines. To indirectly correlate compliance with clinical guidelines with a possible continuous improvement during the intervention period, The present study does not analyze the administration time of the prophylactic antibiotic. This limitation arises from the hospital’s model, which makes it challenging to obtain precise information on the exact timing of medication application. However, as of June 2022, a pharmacy was established in the surgical ward to monitor medication administration times. A further methodological limitation of this study is the lack of a calculated sample size for the periods under comparison. Rather, the analysis encompassed all surgeries conducted within the respective time frames. This could influence the results obtained. Another limitation is the long duration of this study, as multiple external factors, in addition to the implementation of the AMS, could influence the observed improvement in the selection of surgical prophylaxis. Some factors to consider may include the possibility that prescribers may have received information related to the appropriate prescribing of antibiotic prophylaxis for surgery from other institutions and the potential impact of new physicians on the post-AMS group.Despite the factors mentioned earlier, the AMS program at this hospital is among the first of its kind in the country, and the rate of new doctors joining the hospital is low due to the absence of residency programs. Additionally, the development of AMS programs in the region is limited, the education related to this topic at the pre-graduate level is insufficient, and evidence suggests that antibiotic prophylaxis is a cause for concern in Latin America ,16,19. TWe conducted a single-center retrospective quasi-experimental design with patient matching at a 78-bed private hospital in San José, Costa Rica. Two study periods were defined: the pre-AMS period (January to June 2013) and the post-AMS period (June to December 2020). These two periods are related to the audit of all surgical procedures performed in the hospital for six months in each period. The pre-AMS audit demanded a significant investment of time and resources, rendering it impractical to conduct a re-audit during the implementation period, as no major changes were expected. The intervention period began in 2015 and continued for five years.The intervention involved the implementing a surgical prophylaxis guideline. We conducted both group and individualized education sessions, progressively targeting specific medical specialties throughout the intervention. Furthermore, we shared educational materials, continuously monitored outcomes through performance indicators, and conducted both prospective and retrospective audits, providing individualized feedback based on our findings.In this hospital, the surgeons perform mostly elective procedures, so there is not a significant difference in the types of surgeries throughout the year. The study included all patients who underwent a surgical procedure at the hospital during the designated timeframe and received antibiotic prophylaxis.The information was obtained from the electronic clinical records of the hospital. The following were obtained: date, type of procedure, the physician in charge, antibiotic used as prophylaxis, and duration of prophylaxis.The main outcome was to measure the difference in the proportion of the selection of optimal antibiotics for all surgical prophylaxis in the two periods of the study. An optimal selection was considered when the prescription complied with the antibiotics recommended in the previously mentioned guidelines, which are based on Bratzler’s guidelines . SecondaAdditional measures performed included monitoring of antibiotic consumption, adverse drug reactions, and incidence of surgical site infections. These secondary variables, due to their easy accessibility, were monitored throughout the established periods. Also, they served as indirect markers to assess the impact of the AMS over the years.Antibiotic consumption was determined using the Anatomical Therapeutic Chemical/Defined Daily Dose (ATC/DDD) index . Doses wt-test was utilized for normally distributed data, while the nonparametric Mann–Whitney U test was used for data that lacked normal distribution. The data were subjected to a comprehensive statistical analysis using Excel and the most recent version of SPSS Software.Statistical methods such as the Chi-square and Fisher tests were employed to compare appropriate antibiotic selection and treatment duration. To assess antimicrobial consumption, an unpaired Ethical approval to conduct this study was obtained from the Scientific Ethical Committee of the University of Medical Sciences (CEC-UCIMED), approval date 2 June 2021, and reference number CEC-0312-2021. Written consent was not necessary for this study.Implementing an AMS in the surgical ward of a Latin American hospital can lead to significant improvements in both the selection and duration of surgical antibiotic prophylaxis for cesarean deliveries and orthopedic surgeries. This may lead to a decrease in the use of ceftriaxone and a heightened preference for alternative agents like cefazolin. Importantly, the study found no noteworthy detrimental effects or increase in surgical site infections among patients who received improved antibiotic prophylaxis. This demonstrates the program’s success in optimizing antibiotic use without compromising patient safety.


Nowadays, FRP composites are widely applied in the construction industry. Their inherent characteristics are used to strengthen structural elements made of various materials and to increase their durability. The following paper contains the results obtained in a conducted research program aimed at determining the ability to improve the durability of epoxy resin modified with the sonication process, microsilica and carbon nanotubes. The adhesive modified was used to adhere a CFRP tape to a concrete surface. Changes in the viscosity, physicochemical parameters and adhesion of the resin were studied. Selected parameters of the concrete substrate prepared using the sandblasting method, determined with the contact profilometry, were also taken into account. During the tests, attention was paid to the thorough execution and preparation of the samples. As a result of the research, it was demonstrated that the adhesion of the modified epoxy adhesive to concrete could be increased by approximately 28% in the case of the addition of carbon nanotubes and by up to 66% in the case of the addition of microsilica. The modifications used, in addition to increasing the adhesion of the resin to the concrete substrate, were also aimed at reducing the weakening of the adhesive joints caused by oxidation of the resin over time. The results obtained will serve as a basis for evaluating the possibility of their use in the practical reinforcement of structural reinforced-concrete elements. FRP (Fiber-Reinforced Polymer) composites are a specific and very interesting group of composite materials. They are produced in the form of materials combining the properties of selected fibers  as a filling and as matrixes in the form of resins, usually epoxy, phenolics and polyester. Their very good mechanical parameters, primarily their high tensile strength and modulus of elasticity , are theThe relatively small value of deformation influences the specific manner of their failure under testing or working conditions in the structure. FRP composites are most often found in the form of tapes, mats or rods , which, −Reinforcing the structure by gluing and/or anchoring tapes and mats on the surface of the elements ;−Reinforcement of reinforced-concrete elements with FRP bars ,14;−Prestressing of tapes and bars ,14,15;−Prestressed structures with reinforcement in the form of prestressed cables together with the use of appropriate anchoring systems ,17,18.In building structures, FRPs are used in several distinct roles:adhesio) is a difficult phenomenon to define unambiguously, different models of it are analyzed, depending on individual elemental factors. The works in [The bonding of composites to reinforced components is achieved in several ways. The most popular of these is bonding using adhesives polymers, such as epoxy resins ,4,6. In works in ,20,21 deIn the bonding between concrete and CFRP tape, mechanical adhesion and adsorption play the greatest role. This is primarily due to the topography of the substrate and the physicochemical state of the adhesive at the time of application and after curing. Changes in mechanical adhesion are possible due to modifications of the surface to which FRP composites are adhered. Variations in roughness lead to a system in which the glue and substrate can dovetail each other ,24. The The effectiveness of bonding FRP composites to concrete also depends largely on the occurrence of adsorption forces. According to Epoxy resins have functional groups at the ends of polymer chains. Their structure also contains free electrons in the form of clouds located between polymer chains. When applying a resin to a substrate, they may participate in the formation of bonds. It is possible to appropriately modify the polymer to achieve this effect. One way is to use sonication, as the author also described in . CavitatThe process of changing the reactivity of the adhesive can also be influenced by so-called powder fillers, which are additives to polymers that change their basic properties, primarily functional, rheological and mechanical ,32,33. DProper mixing of the filler with the polymer can be achieved in several ways. Among these methods are mechanical mixing, using pressure changes, or sonication. As a result of mixing the phases, i.e., a polymer (liquid) and a filler (solid), a homogeneous mixture is formed, which is then subjected to a crosslinking reaction involving the hardener ,36,38,39The aim of the research presented in this article was to analyze the possibility of increasing the adhesion of the selected epoxy glue to the sandblasted concrete surface. This effect was achieved by modifying the adhesive through the addition of microsilica, multilayer carbon nanotubes and the process of sonication. The reason for choosing such fillers is their different structure. Microsilica is characterized by spherical particles with a polar structure, while nanotubes have a crosslinked structure that can be broken down and straightened. In this way, the expected effect of the interaction between the fillers and the polymer was different. Glue with a base addition of quartz flour was selected for the study for use in the system of strengthening of structural elements with CFRP tapes. An indicator of the effectiveness of bonding with the modified adhesive was the peel strength of CFRP tape fragments bonded to concrete, tested using the pull-off method. Possible changes occurring in the resin structure under the influence of the described modifications were determined. Changes in rheological and physicochemical parameters were examined as auxiliary parameters determining the bonding efficiency: viscosity, contact angle, temperature and surface free energy. The results also depended on surface roughness parameters determined via contact profilometry.The main material that was tested was an epoxy adhesive  used in a system for reinforcing structural members with CFRP tapes (designated as the SD in the study). This adhesive is characterized by the presence of quartz powder as a base filler. The binder is an epoxy resin. The amount of powder in the total volume of the adhesive is about 60%. The properties of the adhesive are shown in Modification by means of sonication;Modification with the addition of microsilica in the amount of 0.5% in relation to the mass of resin;Modification with the addition of carbon nanotubes in the amount of 0.1% in relation to the mass of resin.In the initial phase of the study, the adhesive was subjected to the three modifications:3, an average particle diameter of 0.1µm and a specific surface area of 20,000 m2/kg.Microsilica, BASF , with a density of 2.2 g/cm3, average diameter of 9.5 nm, average length of 1.5 μm and specific surface area of 250–300 m2/g.NanocylTM NC7000 carbon nanotubes, manufacturer NANOCYL , with a density of 1.3–1.4 g/cmIn series with filler additives, sonication was used as a method to allow the adhesive to mix with the fillers. Similar studies were described in . The parThe formulations and designations of each series of samples are shown in Preparation of adhesive in the process of sonication—sonication was carried out using a portable sonicator UP 400S  with a power of 400 W, amplitude equal to 1, range of used power 100% and frequency 20 kHz; in the case of the modified series the sonication time was 6 min, which allowed a uniform structure composed of mixed substances to be obtained;Measurement of adhesive viscosity—this is a parameter largely determining the adhesion of the adhesive to the substrate during its application, and it was determined for all series; the value measured for the SD series at 22 °C served as a reference value, and was measured using a stationary rotational viscosity meter type H2 from FungiLab . Additionally, from the moment the sonicator was turned off, viscosity and temperature were measured  at 5 min intervals until the adhesive cooled to the initial temperature of 22 °C; a diagram showing the stand for sonication and viscosity measurements is shown in Measurement of surface free energy—the SFE was used to describe in detail the phenomena that may occur at the interface between the adhesive and the concrete substrate during the application. From among several methods of SFE measurement described in the literature, the Owens–Wendt method was chosen. Thanks to this, it is possible to determine the polar and dispersion components at the phase interface on the basis of measurements of the wetting angles of drops of two reference liquids with known dispersive–polar parameters; in the described studies, these were distilled water and diiodomethane ; these pMeasuring the adhesion of the adhesive to the concrete substrate—after taking post-measurements before the hardening, the next step was to check the effectiveness of the adhesive with regard to the possibility of increasing the adhesion of the resin on the sandblasted concrete surface. In order to make the tests possible, the samples were made of concrete of class C30/37; the concrete class was dictated by the adhesive manufacturer’s requirement that the concrete peel strength should be at least 2 MPa. In the case of concretes of lower classes, this condition would not always be met. The concrete samples were dried and subjected to the sandblasting process 200 days after being formed; for the surface prepared in this way, the profilometric measurements were taken using a T8000 RC120-400 contact profilometer from Homme-Etamic , then 2.5 × 3 cm pieces of the CFRP tape were glued to the concrete surface using modified adhesives. The size of the CFRP tape specimens was dictated by the parameters of the pull-off Dynatest device  having a load range of 0–25 kN, which was used to detach them from the concrete surface. Four detachment tests were performed for each series; the device and the view of the tape on the concrete surface are shown in The research program included several successive research phases:The results of viscosity measurements at a reference temperature of 22 °C are shown in 2 (similar to quartz powder), allows better filling of the free spaces between the epoxy adhesive chains that remain after the sonication process. In addition, microsilica particles are able to form temporary van der Waals bonds with the mers, which, in effect, due to the thickening of the resin structure, contributes to an increase in viscosity of about 62%. In the studies reported in [From the data presented in orted in ,48, the orted in ,49,50,51orted in ,53, it worted in , among oFurther analysis of the adsorption properties of the adhesives of the various formulations included examinations of wetting angles and surface free energy. The results presented in 2, with a total SFE of 72.8 mJ/m2. The opposite is true for diiodomethane, which, as a highly dispersive liquid, has a total SFE value of 50.8 mJ/m2, of which the dispersive component is as high as 48.5 mJ/m2 [The analysis of the results of wetting angles  should b.5 mJ/m2 ,58,59. T.5 mJ/m2 ,59. The ku parameter. If its value is ≈3, it means there are elevations with smooth surfaces and steep slopes of depressions.The concrete substrate to which the CFRP tape sections were glued was thoroughly cleaned and sandblasted before gluing. After this process, measurements were made with a contact profilometer to determine the height and amplitude parameters. Their results are shown in v, the width of the grooves Rsm and the arithmetic factor of the coordinates of the profile deviations Ra. The other parameters have an important auxiliary function in evaluating the profile parameters. The influence of mechanical adhesion and the way the adhesive penetrates the irregularities depends most on these values.The effectiveness of bonding is most influenced by three factors: the depth of the cavities RAs the final stage of the study, the pull-off measurements were performed. Their results are shown in Among the modified formulations, the series adhered with adhesives with microsilica (66.1% increase) and carbon nanotubes (27.8% increase) showed an increase in adhesion. In contrast, a decrease of 15.7% was recorded for the SD/S series. The differential impact of each of the modified series is clearly seen. In the case of the SD/S series, the adhesive reached a lower final viscosity compared to the unmodified adhesive. This translated into some specific changes in the values of the SFE components, primarily a decrease in the value of the polar component. As a result, it contributed to lower adhesion under the CFRP tape bonding conditions. This is due to the lesser contribution of the adhesion. It is known that cavitation in the SD/S series caused secondary organization of the resin structure, especially the resin binder ,43. In tThe increase in the adhesion of the SD/S/N series should be explained somewhat differently. This adhesive, as shown in Additionally, as can be seen in The conducted research demonstrated the validity of using sonication as a method of modifying the adhesive, but with the additional use of fillers. The SD/S series showed no increase in adhesion (15.7% decrease). In this case, the use of microsilica, which allowed the adhesion of the adhesive to the sandblasted concrete substrate to be significantly increased (by approximately 66%), was justified. For the carbon nanotubes, the impact on the increase in adhesion was smaller but also significant (approximately 28%). Viscosity, SFE and adhesion of the adhesive to the substrate are reliable indicators for assessing the effects of modification and explaining the phenomena occurring in the adhesive structure under the influence of sonication. However, the changes in these parameters are varied, as shown by the results in


With the introduction of national lockdown due to COVID-19 beginning March 2020, there was a significant reduction in the level of antibiotic utilisation rates of 0.707 (p = 0.022). Subsequently, the monthly trend showed a slight upward change until the end of the study period (p = 0.583). Our findings indicate that there was a significant decrease in antibiotic utilisation for systemic use in primary care following the COVID-19 pandemic compared with the preceding years (January 2018–March 2020).The COVID-19 pandemic has resulted in a dramatic change in the delivery of primary healthcare across the world, presumably changing trends in consultations for infectious diseases and antibiotic use. This study aimed at describing and evaluating the impact of COVID-19 on antibiotic use in public primary care clinics in Malaysia between 2018 and 2021. Data from the nationwide procurement database of systemic antibiotics from public primary care clinics in Malaysia between January 2018 and December 2021 were analysed using interrupted time series analysis. The monthly number of defined daily doses per 1000 inhabitants per day (DID) was calculated and grouped by antibiotic class. The trend of antibiotic utilisation rates had been decreasing by 0.007 DID monthly before March 2020 ( Coronavirus disease 2019 (COVID-19), a viral illness caused by SARS-CoV-2 infection, has had an unparalleled impact on the Malaysian healthcare system. Malaysia reported its first case of SARS-CoV-2 on 25 January 2020, and subsequent widespread local transmission culminated in a nationwide lockdown on 18 March 2020 [Research into the use of antibiotics during the COVID-19 pandemic suggests changes in antibiotic usage patterns in both primary and secondary care ,3,4. In Antimicrobial resistance (AMR) is a gradual but implacable process and has been deemed a pandemic itself . An asseOverall, the antibiotic utilisation rate was 1.074 DID in 2018, increasing slightly to 1.203 defined daily doses per 1000 inhabitants per day (DID) in 2019. The rates subsequently dropped to 0.399 DID in 2020 (66.9% reduction) and changed little in the year 2021 (0.410 DID). A total of 7 antibiotic classes and 17 antibiotics were included for analysis. The analysis was stratified by states to compare trends in antibiotic utilisation rates at the state level . ConsistOf the WHO AWaRe antibiotic classification groups, only ‘Access’ and ‘Watch’ category antibiotics were used during the study period. Of the 17 antibiotics analysed in this study, 4 were from the ‘Watch’ category: ceftriaxone, cefuroxime, azithromycin, and erythromycin ethyl succinate . Cefuroxime and ampicillin were the only 2 antibiotics that were utilised more in 2021 than in 2019. The proportion of ‘Access’ category antibiotics used increased from 91.2% in 2018 to 93.2% in 2019. This remained fairly stable over the next 2 years at 94.3% and 93.9% in 2020 and 2021, respectively.p = 0.659) (p = 0.022). After March 2020, the monthly trend showed a slight upward change until the end of the study period (p = 0.583). At 21 months post-onset of the pandemic, antibiotic utilisation was 48.1% lower than would be expected had the pandemic not occurred. At the state level, regression analysis conducted for the respective states was largely nonsignificant. Detailed results are described in = 0.659) . With thp = 0.0018).The Cumby–Huizinga general test for autocorrelation in time series in addition to the autocorrelation function (ACF) and partial autocorrelation function (PACF) tests  indicateThis study provides a description of antibiotic utilisation in primary care for the public sector before and during the period of the COVID-19 pandemic between January 2018 and December 2021. We used interrupted time series analysis (ITSA) to assess the impact of COVID-19 on antibiotic utilisation rates and estimate the size of the changes over time.Prior to COVID-19, the rates of antibiotic utilisation in public primary care in Malaysia showed a decreasing trend, albeit not statistically significant. The impact of COVID-19 can be observed as there were immediate changes, with a significant decrease in antibiotic utilisation rates, following the ‘intervention’ (COVID-19) when compared with before. This was followed by a slight rise in the period thereafter; however, this increase in antibiotic utilisation post-COVID-19 was statistically nonsignificant, likely due to fluctuations in antibiotic utilisation following COVID-19 that had yet to stabilise. Several states in Malaysia underwent shorter and much less extensive lockdowns in the period that followed the initial nationwide lockdown. This could have resulted in varying levels of changes in antibiotic utilisation at the state level. The decrease in utilisation (approximately 60% of pre-pandemic utilisation) may not necessarily be sustained once COVID-19 becomes endemic, as antibiotic utilisation may increase and return to pre-pandemic levels.The results from this study are similar to those reported elsewhere. A study from China reported a drop in the level of antibiotic utilisation 2.8%) due to COVID-19, with a slight increase 0.3%) in the subsequent monthly antibiotic prescription rate . Nationw% due to % in the Chlamydia trichomatis or susceptible Neisseria gonorrhoea. We can conclude that the use of formulary control is seen to be effective in curbing unnecessary use of antibiotics while limiting access to ‘Watch’ category antibiotics during the pandemic. Nevertheless, the increased use of cefuroxime in the last year of our study is cause for concern and should be investigated to prevent a continued substantial increase.The AWaRe classification of antibiotics was developed in 2017 by the WHO Expert Committee on Selection and Use of Essential Medicines as a tool to support antibiotic stewardship efforts at local, national, and global levels. Antibiotics are classified into three groups, Access, Watch, and Reserve, taking into account the impact of different antibiotics and antibiotic classes on antimicrobial resistance, to emphasize the importance of their appropriate use . AndrewsThe COVID-19 pandemic has brought about a wide range of changes in the structure of health services, health-seeking behaviours, and drug utilisation. The reduction in antibiotic utilisation rates may be related to lower patient attendance during the lockdown period. Data from the Ministry of Health show a nearly 40% decline in the number of outpatient visits at public clinics, especially during the early part of the COVID-19 pandemic . Due to Our analysis included the period when the National Antimicrobial Stewardship programme for primary care was introduced at the end of 2018, with specific terms of references and clinical pathways for primary care distributed in 2019 [This study has several limitations. Firstly, we used data on the procurement of antibiotics on an aggregate level, which do not include patient-level data. The unit of antibiotic use is monthly purchased volume, rather than prescription or individuals’ data. Secondly, we were unable to identify a suitable control drug to control for history bias due to time-varying confounders as the pandemic had a nationwide effect . ThirdlyFurther studies are needed to fully understand the mechanisms and implications of the observed reduction in antibiotic utilisation. The many long-term effects of COVID-19 on the population’s health are only beginning to emerge . HoweverThis study is reported according to the Strengthening the Reporting of Observational studies in Epidemiology (STROBE) checklist .Malaysia has a population of approximately 32.6 million inhabitants that are unevenly distributed and largely concentrated on the west coast of the peninsula. The health system in Malaysia is composed of the government-funded public sector and fee-for-service private sector. Public primary care clinics include a network of more than 1000 clinics nationwide with wide geographical coverage enabling them to provide a comprehensive range of health services to the community . All pubFrom 18 March to 5 May 2020, a nationwide lockdown was enforced in Malaysia to contain the transmission of SARS-CoV-2. Subsequently, several states underwent localised movement control orders over various periods of time. Other measures implemented were isolation and testing for symptomatic individuals, epidemiological investigations and quarantine of contacts, enforced public education on hand hygiene and use of masks, social distancing, travel restrictions, reduced population mobility, and promotion of telephone consultations [Pre-COVID: January 2018–February 2020;Post-COVID onset: March 2020–December 2021.We used the duration when the first national lockdown was imposed in Malaysia as a clear ‘interruption’ date (18 March 2020) [This is a retrospective time series analysis of antibiotic utilisation in public primary care clinics in Malaysia for the period of 1 January 2018 to 31 December 2021. This study used the national drug procurement data obtained from the database of the Pharmaceutical Services Programme, Ministry of Health Malaysia. The database includes medicine purchasing records of all government health facilities throughout Malaysia. Detailed information about the database is described elsewhere . PopulatData for antibiotics were retrieved according to the 2020 World Health Organization (WHO) Collaborating Centre for Drug Statistics Methodology Anatomical Therapeutic Chemical (ATC) classification system . We inclThe volume of antibiotic utilisation was calculated based on total number of antibiotics purchased and its defined daily dose (DDD) as defined by the WHO . The ratWe constructed a monthly time series of antibiotic DID to describe the rates of antibiotic utilisation between January 2018 and December 2021. ITSA with segmented regression analysis were conducted to determine whether there was a measurable change in antibiotic utilisation rates associated with COVID-19. ITSA is a quasi-experimental research design for evaluation of longitudinal effects of interventions in incidents. A noteworthy strength of ITSA in evaluating the impact of policy changes using observational data is that the approach controls for the effect of secular trends in a time series of outcome measures. The ITSA design and use of segmented regression allows for assessment of a change in level  and change in slope associated with the intervention or change in policy while controlling for the overall trend in the outcome rate of interest ,30. A toAn ITSA regression model was fitted for the outcome measure (antibiotic utilisation) with the following equation:t is the outcome variable measured monthly; t0 is the time (months) elapsed since January 2018; COVID19 is a dummy indicator representing the impact of the COVID-19 pandemic with a value of 0 (before March 2020) and 1 (March 2020 onwards); and taft_COVID19 is the time after the pandemic began to have an impact. In this model specification, β0 represents the baseline level of the outcome. β1 is the change in antibiotic utilisation that is independent from the COVID-19 pandemic period. β2 captures the change in the level of antibiotic utilisation that occurred immediately following the pandemic, and β3 represents the change in the trend of antibiotic utilisation following the COVID-19 pandemic. The error term εt at time t represents the random variability unexplained by the model [In this model, Yhe model ,32.All the tests considered the two-sided significance level of 5%. Testing for stationarity, a key assumption in time series analysis, was conducted using the ADF unit-root test. The null hypothesis of the ADF test is that there is a unit root in a time series sample, implying that the data series is not stationary .Autocorrelation may lead to underestimated standard errors and overestimated significance of the effects of an intervention . CorreloAutocorrelation was also tested using the general specification test of serial correlation in a time series proposed by Cumby and Huizinga . The nulOur findings indicate that there was a significant decrease in antibiotic utilisation for systemic use in primary care following nationwide lockdown during the COVID-19 pandemic compared with the preceding years. Given the context of increasing antimicrobial resistance and telemedicine, prudent and judicious use of antibiotics is pertinent to global health and wellbeing. Further research is needed to assess the long-term impact of the COVID-19 pandemic, as primary care management of common respiratory tract infections has been largely affected by changes in testing and vaccination strategies.