This study aimed to describe prescription of antibiotics to the elderly population in general practice in Denmark from 2010–2017.This is a national register-based observational study.General practice, DenmarkThe main outcome measure was prescriptions/1,000 inhabitants/day (PrID) in relation to year, age and sex, indication, and antibiotic agent.In this study, we included inhabitants of Denmark, ≥65 years of age between 01st July 2010–30th June 2017.A total of 5,168,878 prescriptions were included in the study. Antibiotic prescriptions decreased from 2.2 PrID to 1.7  PrID during the study. The decrease in PrID was most noticeable among 65–74-year-olds (-25%). The ≥85-year-olds were exposed to twice as many PrID than the 65–74-year-olds, but only accounted for 20% of the total use. Urinary tract infection (UTI) was the most common indication for antibiotic prescription and increased with advancing age. The most commonly prescribed antibiotics were pivmecillinam and phenoxymethylpenicillin. Prescribing with no informative indication was present in one third of all cases.High antibiotic use among elderly is well known and studies indicate mis- and overuse within this population. Our study shows.The prescription rate is decreasing within all age groups of the elderly population.The ≥85-year-olds receive twice as many prescriptions/1000/day as the 65–74-years-olds.The prescription of antibiotics in the elderly population in general practice decreased from 2010 to 2017. The oldest age group was exposed twice as frequently to antibiotic prescriptions as the 65–74-year-olds. The smallest reduction was observed for the ≥85-year-olds, suggesting targeting interventions at this group. The unprecedented increase in antibacterial resistance rates is a serious threat to public health . AntibioDuring the last decade, Denmark has seen a decrease in the use of antibiotics for all age groups, except for the elderly ≥80 years . CurrentThe elderly population is at increased risk of many infectious diseases, including urinary tract infections (UTI) and respiratory tract infections (RTI), in turn exposing them to the consequences of antibacterial resistance, such as increased mortality and morbidity ,10. FurtThe projected rise in the number of elderly in combination with the increase in infectious diseases requiring antibiotic treatment among this group, implies that it is important to understand current patterns and trends in prescriptions of antibiotics within this group. Unfortunately, detailed information on antibiotic use in the elderly population is still scarce. An international study from 2017 found that on a given day 10.5% of long-term health care facility residents in Denmark received antibiotic treatment . This plTo this end, we conducted the present study to describe trends of antibiotic use by year, age group, clinical indication and antibiotic type among the elderly population in Denmark from 2010–2017.This is a register-based observational study, describing antibiotic prescriptions in general practice among the elderly population in Denmark from 2010–2017. The study population was all Danish elderly aged ≥65 years or more. Data on antibiotic prescriptions were obtained from the Danish National Prescription Registry. This registry contains comprehensive and complete information on all reimbursed prescriptions redeemed by Danish inhabitants at outpatient pharmacies since 1995 . The folA dataset consisting of antibiotic prescriptions from general practice was constructed using the unique practice identification number.supplementary materials. DDD is the average maintenance dose per day for a drug used for its main indication, as defined by the World Health Organization [Supplementary Table S1 + S2.The primary outcome measure for antibiotic prescriptions was calculated as the number of prescriptions/1,000 inhabitants/day (PrID). Results in Defined Daily Dose (DDD)/1,000 inhabitants/day (DID) are provided in nization . All resTable S3. Prescriptions with indications obviously not associated with justifiable antibiotic prescribing such as ‘high blood pressure’ were excluded as these were regarded as a mistaken entry by the GP or system errors at pharmacy level. DDD values less than one per package were excluded. Observations with more than 10 redeemed packages at once were likewise excluded.In Denmark, the general practitioner (GP) must select a suitable clinical indication from a pre-specified drop-down list when prescribing an antibiotic treatment. If no suitable indication is available, the GP can enter a free text as indication, but this information is not available for data extraction. Until 2014 the GP could choose the indication ‘unspecified infection’ . Based oTo account for varying seasonal changes in specific infectious diseases, a yearly measure was constructed from 01st July 2010–30th June 2011 and so forth, to ensure a complete winter season within each year. For these yearly measures, we used the specific population of elderly ≥65 years of Denmark on January 1st for each study year  in the analyses.www.statistikbanken.dk.The study population was divided into the three age groups; 65–74 years, 75–84 years and ≥85 years. When dividing the population according to age groups, the population size for the specific age group was used to calculate PrID and DID to enable inter-group comparisons. Data regarding population statistics was collected from Change over the study period in percentages was assessed in a linear regression of logarithm transformed PrID and DID on time. All data work was performed in SAS Software version 9.4 .From 2010 to 2017, the Danish elderly population increased by 17.3% from 933,781 to 1,095,172 individuals. The general population characteristics are shown in n = 7,703), with DDD values < one per package (n = 384) and with > 10 redeemed packages (n = 272), 5,168,878 prescriptions were included in the study.From 1st July 2010–30th June 2017, a total of 5,177,237 prescriptions were identified. After exclusion of prescriptions with indications not associated with antibiotic prescribing , while DID decreased from 23.5 to 20.3  during the study period . PrID deAn increase in all specific indications was observed as missing indications decreased to approximately 30% over the study period. UTI constituted the majority of the available indications for all years and age groups. However, an absolute decrease in PrID for UTI was observed during the study. RTI increased relatively by 50% and absolutely by seven percentage points. This pattern was present in all age groups. Similarly, SSTI increased by eight percentage points.UTI was the most prevalent indication in age group ≥85-year-olds across time accounting for 77.3% of all available indications (excluding ‘missing indication’), compared to 53.0% in the age group 65–74 years and 65.8% in 75–84 years. RTI and SSTI accounted for 29.3 and 13.1% of the available indications in the youngest age group, 21.8 and 10.0% in the 75–84-year-olds and 13.2 and 8.1% in the oldest age group.In all, penicillin (J01C) constituted approximately 50% of the antibiotic consumption in the elderly population . The relative consumption of this group of antibiotics increased for all age groups during the study period. This relative increase was due to an absolute increase in PrID of pivmecillinam and amoxicillin and beta-lactamase inhibitor and the overall absolute decrease in total PrID. Prescriptions of quinolones remained stable during the study, constituting approximately 5% in 2016–2017, in all age groups which corresponds to an actual decrease in the total amount of PrID from 0.13 to 0.09.For the entire study period, the top three agents used for UTI made up 73.7% of all prescriptions labelled UTI; pivmecillinam (39.6%), sulfamethizole (16.9%) and trimethoprim (17.2%). Likewise, prescriptions labelled RTI were dominated by phenoxymethylpenicillin (38.2%), amoxicillin and beta-lactamase inhibitor (27.6%) and roxithromycin (14.3%) accounting together for 80.1% of this indication. During the study period a trend in prescriptions labelled RTI was noted where the proportion of phenoxymethylpenicillin decreased from 41.1% to 36.6%. Conversely, amoxicillin and beta-lactamase inhibitor increased from constituting 18.2% to constituting 30.8% of all prescriptions labelled RTI. For prescriptions labelled SSTI, the most frequently prescribed agents were phenoxymethylpenicillin (38.1%), dicloxacillin (36.1%) and flucloxacillin (8.2%) which together made up 82.4%. Prescriptions labelled Others were dominated by ciprofloxacin (32.9%), phenoxymethylpenicillin (20.4%) and dicloxacillin (16.4%).In this study, we have characterized the prescriptions of antibiotics in general practice among the elderly population in Denmark from 2010–2017 by year, age group, clinical indication and antibiotic type.PrID decreased from 2.2 to 1.7 over the seven-year study period. The ≥85-year-olds were exposed twice as frequently to antibiotic prescriptions as the 65–74-year-olds. This difference was likely driven by a higher number of UTI treatments in the ≥85-year-olds. A lower decrease was observed among men (−7.5%) than women (−19.2%) in age group ≥85-year-olds.Throughout the study period, pivmecillinam and phenoxymethylpenicillin were the most prescribed antibiotic agents. In Denmark, pivmecillinam is generally first choice treatment for UTIs and phenoxymethylpenicillin for most RTIs. As UTI and RTI was the most common indications, this indicate that the choice of antibiotic type is based on current guidelines. Furthermore, the top three antibiotic agents prescribed for UTI, RTI and SSTI accounted for 73.7%, 80.1% and 82.4% of the total amount of prescriptions respectively, indicating that GPs tend to prescribe the same type of antibiotics for the same indications. Fluoroquinolones are decreasingly used in Danish general practice and made up only approximately 5% of the total use. Worryingly, a slight increase in prescription of amoxicillin with beta-lactamase inhibitor was noted, as this is on the watch list in WHO AWaRe index.Certain strengths and limitations of the study need to be addressed. First, we chose to primarily report the results in PrID, as this unit is perceived more clinically understandable. Some clinicians may only have vague references for DDD or DID values, compared to PrID. Furthermore, when using prescriptions and PrID as measurements we circumvent the inconvenience of changing guidelines for antibiotic treatment, package sizes and strength of tablets, which may influence the value of DDD, and subsequently DID. On the other hand, when using PrID and DID one does not take treatment failure into account and may therefore not precisely reflect clinical treatment episodes. However, as we set out to examine prescription of antibiotics, we found that PrID was the most sensible measurement.The nationwide scope of the project is a clear advantage as the Danish national registers provide an opportunity to examine almost the entire use of antibiotics in general practice. In Denmark, antibiotics for systemic use are only available by prescription and all redeemed prescriptions are registered in the prescription database, which makes the database complete. While the database is complete in this regard, one-third (2016–2017) of the prescriptions did not have an informative clinical indication. As noted by Aabenhus et al. , it is iIn line with DANMAP , our stuThe present decrease in the antibiotic prescription rate is concurrent with a slight, but significant decrease in the resistance rates of E. coli from urine samples in primary health care. This could lead to less treatment failure and hence lower the antibiotic prescribing rate, but as the general resistance rate in Denmark is low , this maIn the Danish National Action plan from 2017 , a natioWhen comparing the rate of antibiotic prescriptions in the different age groups, it was evident that the ≥85-year-olds had a very high use of antibiotics. The reason for this is unknown but may lie in the considerably higher proportion of institutionalized individuals, for which a high use of antibiotics is well known. Within the group of institutionalized individuals, UTI is a central driver of the high prescription rate due to the following: high incidence of UTI, high prevalence of ASB , difficuFurthermore, infectious diseases in this group is more often accessed and communicated second hand through care takers, which can complicate the diagnostic process and hence treatment decision.Finally, this study enables the identification of patterns of antibiotic use within the elderly population and proposes potential interventions aiming to reduce and rationalize antibiotic use. This study also indicates that the interventions already implemented in Denmark  has been somewhat successful. However, it is important to remember that antibiotic treatment is sometimes of great importance for especially frail elderly. Knowledge on how to reduce antibiotic use without compromising the well-being of these individuals is warranted.In summary, the total antibiotic use in PrID declined from 2010–2017 in the elderly population in general practice, Denmark. This decrease was observed in all age groups, but not evenly distributed. The rate of antibiotic prescriptions increased with older age. This was especially the case for UTI treatments. The largest proportion of antibiotic prescriptions were prescribed to the 65–74-year-olds due to the larger population size of this group. Interventions to reduce unnecessary antibiotic use among the oldest and to reduce overprescribing for UTI are two possible relevant targets to effectively lower antibiotic use in the future.Click here for additional data file.


The transition between seed dormancy and germination is an important ecological trait and a key stage in the life cycle of higher plants. According to our observations, the seeds of Zostera marina L. (eelgrass) in Swan Lake (SL) and Qingdao Bay (QB) in northern China have the same maturation time (summer) but different germination time. To investigate this phenomenon, we further carried out reciprocal transplantation experiment and transcriptome analysis. Results revealed that differences in the seed germination time between the two sites do exist and are determined by internal molecular mechanisms as opposed to environmental factors. Furthermore, we conducted comparative transcriptome analysis of seeds at the mature and early germination stages in both locations. The results that the number of genes related to energy, hormone and cell changes was higher in SL than in QB, could account for that the dormancy depth of seeds in SL was deeper than that in QB; consequently, the seeds in SL needed to mobilize more related genes to break dormancy and start germination. The results could have important practical implications for seagrass meadow restoration via seeds and provide in-depth and comprehensive data for understanding the molecular mechanisms related to seagrass seed germination.Seagrasses are the only submerged marine higher plants, which can colonize the sea through sexual ( The time of seed maturation (summer time) is same in both places, but the time of germination is totally different. Seed germination in QB began in autumn of the same year as seed maturation, and most seeds germinated in October and November. In contrast, the seed germination period in SL is in spring of the year following seed maturation, from March to the end of May. Globally, a number of studies have found that the germination seasons of different geographical populations of eelgrass differ. For example, the seeds of eelgrass populations in the northeastern Pacific Ocean mainly germinate in spring and autumn  is a marine lagoon in Weihai City, northern China covering an area of 4.8 km2 . SL is c2  and expe2 . This la present . Zosteradal zone , 2020; wdal zone , 2019. TZ. marina, but there also occurs a small area of Z. japonica. The distribution and shoot height  is an open bay in Qingdao City, northern China . The tidt height  of the tZ. marina with spathes containing seeds were collected by hand from QB and SL in July 2017. Reproductive shoots were transported to the laboratory, where they were stored in a 600-μm mesh bag and placed in an aerated flow through tank (1 m × 1.2 m × 1.5 m). Mature seeds were naturally released from the flowering shoots and were then collected and sieved to remove any detritus and larger material. Following this, all seeds were kept in a running seawater tank until the initiation of seed reciprocal transplanting.Reproductive shoots of Eelgrass seeds from SL were planted in QB on 21 August 2017. Seeds were placed in 12 polyvinyl chloride tubes . Plastic mesh caps (1 mm × 1 mm) were placed at the bottom of each of the tubes, and the tubes were filled with dry sediment collected from the banks of QB. The sediment was saturated with natural seawater. Intact and full eelgrass seeds were selected, and groups of 50 seeds were planted in each tube at a burial depth of ~2–3 cm . Plasticin situ  carefully in situ , and thein situ .All statistical analysis was carried out using R statistical software version 3.6.2 . Values Z. marina with spathes containing seeds were collected by hand from QB and SL in July 2019. Collection and transportation of reproductive plants and harvesting of mature seeds was the same as described in section “Seed Collection in Experiment 1”. Molecular samples of mature seeds from the two sites were collected and named as QB-M and SL-M. The remaining seeds were kept in a circulating tank at room temperature in seawater. The status of seeds was observed once every 15 days until November, when the seeds collected from QB began to germinate in large numbers. By this time, molecular samples of seeds from QB (seeds in the germination stage but not yet germinated) and SL (seeds in the dormant stage and not germinated) were collected and were named as QB-G and SL-N, respectively. In March 2020, the seeds in the water tank collected from SL began to germinate in large numbers, and molecular samples of seeds from SL (seeds in the germination stage but not yet germinated) were collected at this time (SL-G). All molecular samples were immediately frozen in liquid nitrogen, and then stored in at −80°C. Four replicate samples, with each replicate containing approximately 10 seeds, were collected.Reproductive shoots of Z. marina seed tissue using TRIzol® Reagent (Plant RNA Purification Reagent) according the manufacturer’s instructions and genomic DNA was removed using DNase I. The RNA was tested for concentration, purity, and integrity, and only high quality RNA was used for library building OD260/280 = 1.8–2.2, OD260/230 ≥ 2.0, RIN ≥ 6.5, 28S:18S ≥ 1.0, >1 μg. The RNA-sequencing (RNA-seq) transcriptome library was prepared using a TruSeqTM RNA sample preparation kit from Illumina  using 1 μg of total RNA. After quantification with TBS380, the paired-end RNA-seq sequencing library was sequenced with the Illumina HiSeq xten/NovaSeq 6000 sequencer (2 × 150 bp read length).Total RNA was extracted from Z. marina was sequenced in 2016 , Swiss-Prot database (Swiss-Prot), the Protein families database (Pfam), Evolutionary genealogy of genes: Non-supervised Orthologous Groups (EggNOG), Gene Ontology (GO) database, and Kyoto Encyclopedia of Genes and Genomes (KEGG) database.The raw paired end reads were trimmed and quality control was carried out with SeqPrep and Sickle software to get high quality clean data. The genome of  in 2016 , and itsp ≤ 0.05 compared with the whole-transcriptome background. GO functional enrichment and KEGG pathway enrichment analysis were carried out by GoatoolsRSEM was used to quantify gene abundance, and the expression level of each transcript was calculated according to the transcripts per million reads method. Different expression analysis was performed using DESeq2 (1.24.0), and genes with p-adjust <0.05 and |log2FC| > 1 were considered to be significantly different expressed genes (DEGs). In addition, functional-enrichment analysis including GO and KEGG were performed to identify which DEGs were significantly enriched in terms of GO and metabolic pathways at Bonferroni-corrected 2O, made up to a total volume of 20 μl. The cycle conditions of RT-qPCR were as follows: the initial step was 95°C for 5 min, and then 40 cycles . The target gene and internal reference gene of each sample were subjected to RT-qPCR reaction. Each treatment group had three replicates, and each replicate sample had three multiple pores. The relative expression level was calculated using the 2−ΔΔCt method. Data were analyzed by t-test, and differences were considered as statistically significant if p < 0.05.To evaluate the reliability of RNA-seq, we randomly selected eight genes (four each from SL and QB) for transcriptome validation using real-time quantitative polymerase chain reaction (RT-qPCR) and 18S rRNA was used as the internal reference gene. The RNA extracted as described in Section RNA Extraction was used as the template for reverse transcription to obtain cDNA. PCR results of the pre-experiment showed that the electrophoresis gel of each primer was a single bright band under specific conditions, indicating no specific amplification, and the primers could be used in subsequent experiments. The reaction system of RT-qPCR was as follows: 10 μl of 2× ChamQ SYBR Color qPCR Master MixPCR, 0.8 μl of both forward and reverse primers (5 uM each), 0.4 μl of 50× ROX Reference Dye, 2 μl of template (cDNA), and 6 μl of ddHSeeds collected from QB had a higher seed germination rate in autumn (mainly November and December), regardless of whether they were planted in QB or SL. The highest germination rate occurred in SL in December 2017 (40.67% ± 1.76%); however, the germination rate was very low in spring . Seeds cWhen a large number of seeds from QB began to germinate in the circulating water tank in the laboratory in autumn, un-germinated seeds from QB and SL were collected for transcriptome analysis. At this time, the seeds from QB should have been in the germination stage (QB-G), while the seeds from SL should have been in the non-germination or dormant stage (SL-N).After transcriptome sequencing of eight samples from QB-G and SL-N were completed, a total of 54.36 GB of clean data were obtained, the clean data of all samples were above 5.89 GB, the percentage of Q30 base was above 93.27%, and the GC content of clean reads was about 44.31%. The clean reads of each sample were aligned with the designated reference genome, and the alignment rates ranged from 89.88 to 92.91%. The Pearson correlation coefficient between biological replicates was greater than 0.97 , indicatp < 0.05). On the whole, these significantly upregulated KEGG enrichment pathways are involved in energy metabolism, lipid metabolism, amino acid metabolism, and biosynthesis of secondary metabolites, which indicted that compared with the seeds from SL in the dormant stage, the seeds in the early stage of germination from QB had begun to initiate multiple metabolic pathways to mobilize the stored energy of seeds and gradually emerge from dormancy and start germination.The upregulated DEGs and uniquely expressed genes in QB-G were integrated into a gene set (QB_up_unique), and KEGG pathway enrichment analysis was performed . FlavonoTranscriptome sequencing of 16 samples from SL-M, SL-G, QB-M, and QB-G was completed. A total of 107.65 GB of clean data were obtained, clean data of all samples were above 5.88 GB, the percentage of Q30 base was above 93.32%, and the GC content of clean reads was about 44.40%. The clean reads of each sample were aligned with the designated reference genome, and the alignment rates ranged from 89.91 to 94.41%. Pearson correlation coefficient between biological replicates was greater than 0.97, indicating good repeatability and that the data are reliable. PCA analysis showed that four groups of samples were separated significantly in the PC1 × PC2 dimension . In the A total of 2,176 DEGs were identified by comparing QB-G and QB-M seeds, including 985 upregulated genes and 1,191 downregulated genes . Meanwhip < 0.0001).KEGG pathway statistics and enrichment analysis were further analyzed for genes in subcluster7 . The stap < 0.01), including seven pathways related to energy metabolism and carbohydrate metabolism: pyruvate metabolism, carbon fixation in photosynthetic organisms, citrate cycle, glyoxylate and dicarboxylate metabolism, propanoate metabolism, glycolysis/gluconeogenesis, and butanoate metabolism. Similarly, upregulated DEGs in QB were also analyzed by KEGG pathway enrichment (p < 0.01), but only two were related to carbohydrate metabolism, which were pyruvate metabolism and glycolysis/gluconeogenesis.Upregulated DEGs in SL were analyzed by KEGG pathway enrichment . There wrichment . There wThe plant hormone abscisic acid (ABA) is a positive regulator of dormancy induction and dormancy maintenance. A total of 38 genes related to ABA were found in the SL DEG set, including 17 upregulated DEGs and 21 downregulated DEGs . FurtherThe plant hormone gibberellin (GA) is a positive regulator of dormancy breaking and germination induction. A total of 15 genes related to GA were found in the SL DEG set, including nine upregulated DEGs and six downregulated DEGs . FurtherGenes related to cell changes were identified in all genes from SL and QB , includiZ. marina observed for many years, the seeds from QB mainly germinate in autumn of the same year as seed maturation, and the seeds from SL mainly germinated in spring of the following year. In this study, we carried out a field experiment transplanting seeds from QB to SL and from SL to QB. The results showed that seeds from QB still germinated in autumn regardless of whether they were planted in QB or SL, and seeds from SL, whether planted in QB or SL, still germinated in the following spring. We also conducted comparative transcriptome analysis in autumn (germination stage of seeds in QB and dormant stage of seeds in SL). The results showed that genes involved in some metabolic pathways, such as energy metabolism, lipid metabolism, amino acid metabolism, and biosynthesis of secondary metabolites, were significantly upregulated in the seeds of QB compared with those of SL, which indicated that the seeds in QB were gradually emerging from dormancy and starting the germination process, while the seeds in SL were still dormant. Therefore, we believe that the factors that determine the seed germination time at the two sites are not environmental factors, but their different internal molecular mechanisms.According to the results of the seed germination time of the natural population of Arabidopsis seed germination, found that the number of genes involved in breaking dormancy or inducing germination was much higher at the post-ripening stage than at the dormant stage . SY, XZ, YQ, and ML: investigation. YZo: funding acquisition, supervision, methodology, investigation, and writing – review and editing. All authors contributed to the article and approved the submitted version.This research was supported by the National Key R&D Program of China (2019YFD0901300), the National Science & Technology Basic Work Program (2015FY110600), the National Natural Science Foundation of China (No. 32000269), the Natural Science Foundation of Shandong Province (ZR2020QD106), the Key Research Project of Frontier Sciences of CAS (QYZDB-SSW-DQC041-1), and the Taishan Scholars Program (Distinguished Taishan Scholars).The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Antibiotic surgical prophylaxis is a core strategy for prevention of surgical site infections (SSI). Despite best practice guidelines and known efficacy of antibiotic prophylaxis in decreasing SSI risk, there is often wide variation in its use. This study was designed to determine the individual perspectives of perioperative providers at an academic tertiary referral center regarding their knowledge of preoperative antibiotic choice, dosing, and timing.A prospective survey was conducted amongst surgical and anesthesia team members involved in preoperative antibiotic decision making. The survey addressed ten key principles relating to preoperative antibiotic use, including antibiotic choice, timing and rate of infusion, and dosing. The survey was distributed among orthopaedic surgeons, residents, and anesthesia providers at their respective monthly service line meetings between August 2017 to June 2019. The data was stored and analyzed in a Microsoft Excel worksheet.A total of 73 providers completed the survey. Twenty-two (30 %) of the providers agreed and 47 (64 %) disagreed that both vancomycin and cefazolin are equally effective for antibiotic prophylaxis. As for antibiotic choice in patients with penicillin allergies, 37 (51 %) agreed with vancomycin, 21 (29 %) agreed with clindamycin, and 15 (21 %) disagreed with both alternatives. When providers were surveyed regarding the appropriateness of standard versus weight adjusted dosing, 67 (92 %) agreed that vancomycin should be weight adjusted and 63 (86 %) agreed that cefazolin should be weight adjusted.There is no clear consensus amongst providers for which antibiotic to administer for antibiotic prophylaxis despite existing guidelines. Discrepancy also exists between orthopaedic surgery and anesthesia providers in regards to appropriate antibiotic choice for patients with reported penicillin allergies. Institutions should implement evidence-based protocols for preoperative antibiotic prophylaxis and continue to prospectively monitor compliance in order to identify any inconsistencies that could result in inappropriate antibiotic prophylaxis for patients. Surgical site infections (SSI) continue to be one of the most common complications after orthopaedic surgery , 2. PatiThe efficacy of antibiotic prophylaxis within the field of orthopaedic surgery is well documented. In total knee and total hip arthroplasty, a study reported an 81 % decrease in risk of SSI with the use of antibiotic prophylaxis compared to without . SimilarConsidering the effectiveness of antibiotic prophylaxis for decreasing the risk of SSI but the potential for great variability in its use despite best practice guidelines, we performed a qualitative study to assess the antibiotic prophylaxis perspectives of the orthopaedic surgery and anesthesiology teams at Virginia Commonwealth University (VCU) Health regarding preoperative antibiotic choice, dosing, and timing.This study was conducted at an 850-bed tertiary care hospital with institutional pre-operative prophylaxis guidelines in place that prefer cefazolin with vancomycin as an alternative for penicillin allergy or an addition for MRSA-colonized patients. An Institution Review Board (IRB) approved survey Fig.  was distA total of 2 orthopaedic NP’s and 25 orthopaedic surgery residents were approached to complete the survey. Both NP’s (100 %) and 22 (88 %) residents completed the survey. A total of 3 providers (13 %) agreed that vancomycin and cefazolin are equally effective for antibiotic prophylaxis whereas 19 (79 %) disagreed, and 2 (8 %) were unsure  attending orthopaedic surgeons completed the survey. Ten (44 %) attending orthopaedic surgeons agreed that vancomycin and cefazolin are equally effective for antibiotic prophylaxis whereas 12 (52 %) disagreed, and 1 (4 %) was unsure Fig. . Nine prTwelve CRNA’s, 6 anesthesia residents, and 8 attending anesthesiologists completed the survey. Nine (35 %) anesthesia providers agreed that vancomycin and cefazolin are equally effective for antibiotic prophylaxis whereas 16 (62 %) disagreed, and 1 4 %) was unsure  or service (anesthesia or orthopaedics) was not observed. However, there was significant disagreement regarding preferred agent for penicillin allergies, with residents more frequently indicating agreement with vancomycin  compared to CRNA’s/NP’s , and attendings . There were also differences between anesthesia and orthopaedics regarding awareness of patients’ MRSA status with 30 (64 %) orthopaedic providers in agreement that MRSA status is known and only 9 (35 %) anesthesia providers in agreement. Lastly, anesthesia was more likely to agree that frequent switches from cefazolin to vancomycin occur at the last minute (17 out of 26 (65 %) in agreement versus 16 out of 47 (34 %) amongst orthopaedic providers).Despite well established guidelines and the known efficacy of antibiotic prophylaxis for reducing the risk of SSI, there continues to be wide variation amongst antibiotic prophylaxis practices. Therefore, we performed this study to assess the perspectives of providers at our institution regarding some of these practices including preoperative antibiotic choice, dosing, and timing. We determined that there is no clear consensus regarding the effectiveness of vancomycin and cefazolin for antibiotic prophylaxis since 30 % of providers agreed and 64 % disagreed that both antibiotics are equally effective. Similarly, there was also no consensus on the antibiotic choice for patients with a penicillin allergy since 51 % of those surveyed agreed with vancomycin, 29 % agreed with clindamycin, and the remaining 21 % disagreed with both alternatives. In contrast, providers did generally agree with necessity of weight based dosing and timely infusion of vancomycin.Overall, the results from this study indicate that there is no clear consensus amongst the providers at our institution when it comes to which antibiotic to administer for prophylaxis against SSI despite institutional guidelines developed by surgical service leadership. Several institutions from all over the world have determined that antibiotic prophylaxis is often inadequately administered. In a study from China that included 53 hospitals and a total of 14,525 procedures, Ou et al. determined that in only 9.4 % of the procedures was antibiotic prophylaxis appropriate and correct in all steps, which included antibiotic choice, dose, dosing strategy, time of administration and duration of prophylaxis . SimilarThe explanations for our results are multifactorial. One reason for the lack of consensus in terms of appropriate antibiotic choice may be due to the fact that best practice guidelines are not widely displayed throughout preoperative and operative areas at our institution. Therefore, lack of awareness could be a potential contributor to our results. Another potential explanation is that since there is no formal education or training for both orthopaedic surgery and anesthesia team members regarding the topic of antibiotic prophylaxis, providers at our institution may not possess the most up-to-date knowledge in regards to this topic. Furthermore, as antibiotic resistance and drug allergies continue to increase in our communities, there is a need to continually educate health care providers on the most current literature available. Thus, an educational gap could be another contributing factor to our results. Lastly, there is also no antibiotic prophylaxis checklist at our institution to help standardize prophylaxis practices, which is often a key component of successful quality improvement initiatives .In contrast to antibiotic choice, there was agreement at our institution that cefazolin and vancomycin dose should be weight adjusted. This consensus is most likely explained by the fact that the electronic medical record (EMR) at our institution prompts physicians to use weight-based dosing when ordering prophylactic antibiotics. We also determined that providers agreed that vancomycin infusion at the time of incision at our institution is often not adequate for antibiotic prophylaxis. This has severe implications because it is well documented that patients with inadequate vancomycin infusion have a significantly higher risk of SSI compared to patients where infusion is complete prior to incision. In a study by Cotogni et al. involving 741 cardiac surgery patients, patients where vancomycin infusion was violated  had greater than five times increased odds of SSI compared to patients where vancomycin infusion was completed prior to incision . ThroughBased on the results from this study, we have determined that there may be many potential areas for improvement at our institution when it comes to antibiotic prophylaxis. However, results of quality improvement programs to improve antibiotic prophylaxis have been mixed. In a study from the University of Texas at Houston, Putnam et al. implemented three cycles of interventions from 2011 to 2014 to improve antibiotic prophylaxis . A few oOur study has several important limitations. First, the study is purely qualitative since we gathered provider data with the use of a questionnaire. Second, the purpose of this study was to only assess the antibiotic prophylaxis perspectives at our institution; we did not perform a retrospective analysis to determine the actual adherence to antibiotic prophylaxis guidelines at our institution. Therefore, although we found no clear consensus amongst our providers when it comes to which antibiotic to administer for prophylaxis against SSI, we cannot determine if this finding directly translates to poor adherence to antibiotic guidelines at our institution. Third, our study is subject to selection bias since our sample size of 73 providers is small and we only surveyed providers involved with the care of orthopedic patients. Furthermore, specific to anesthesia providers, although department meetings are mandatory, not all anesthesia providers were present and thus we were unable to approach all anesthesia team members at VCU Health to complete surveys. Lastly, it is important to mention that these results are based on responses from providers only at one institution.Our survey indicated that there is no clear consensus amongst providers for which antibiotic to administer for prophylaxis against SSI despite existing internally developed and surgery-type specific guidelines. There is also great discrepancy between orthopaedic surgery and anesthesia providers in regards to appropriate antibiotic choice for patients with reported penicillin allergies. Therefore, based on our results, institutions should implement evidence-based protocols for preoperative antibiotic prophylaxis and continue to prospectively monitor compliance in order to identify any inconsistencies that could result in inappropriate antibiotic prophylaxis for patients.


The rapid development of the construction sector has led to massive use of raw construction materials, which are at risk of exhaustion. The problem is aggravated by the high demand for cement as binding powder and the mass production of clay bricks for construction purposes. This scenario has led to high energy consumption and carbon emissions in their production. In this regard, bio-cementation is considered a green solution to building construction, because this technology is environmentally friendly and capable of reducing carbon emissions, thus slowing the global warming rate. Most of the previously published articles have focused on microbiologically induced calcium carbonate precipitation (MICP), with the mechanism of bio-cementation related to the occurrence of urea hydrolysis as a result of the urease enzymatic activity by the microbes that yielded ammonium and carbonate ions. These ions would then react with calcium ions under favorable conditions to precipitate calcium carbonate. MICP was investigated for crack repair and the surface treatment of various types of construction materials. Research on MICP for the production of binders in construction materials has become a recent trend in construction engineering. With the development of cutting edge MICP research, it is beneficial for this article to review the recent trend of MICP in construction engineering, so that a comprehensive understanding on microbial utilization for bio-cementation can be achieved. Cement functions as the conventional binding powder for the production of concrete and mortar. On the other hand, burnt clay bricks are commonly used to build masonry walls for buildings. Concrete is the second most widely used material on earth after water [The construction industry contributes to massive economic and social development around the world. However, it has a broad carbon footprint due to high energy consumption, from the production phase of raw materials to the construction phase of structures. This accelerates global warming, and therefore the melting of icecaps and consequent rising of sea water levels. Such an environmental problem is affecting the quality of life of the world’s population. Concrete, cement mortar, and burnt clay brick have been identified as the building materials that emit carbon dioxide , microorganisms can react with chemical components to produce minerals in the form of organic–inorganic compounds acting as a binding agent . Numeroue cracks . In parte cracks ,10,11,12e cracks , to treae cracks ,15,16,17e cracks ,17, to ie cracks , and to e cracks .A critical review of the MICP applications can deepen understanding of the role of bio-cementation in the construction of sustainable buildings. By assessing mechanical and chemical properties of bio-cemented construction materials, their robustness and durability can be characterized. The scientific evidence is able to pave a clear direction towards refined research on the mechanism of bio-cementation of microorganisms in the production of tangible bio-based construction materials that are comparable to conventional resources. As such, the objective of this article is to provide a detailed overview of bio-cementation in construction materials. In particular, the roles and the effectiveness of different species of microorganisms of inducing calcium carbonate precipitation for construction materials are overviewed.Sporosarcina pasteurii is the most studied species of Bacillus bacteria for MICP applications on cement composites. S. pasteurii are urease-producing bacteria that have the ability to induce sufficient calcium carbonate precipitation for bio-cementation to occur in concrete structures. The mechanism of bio-cementation of the bacteria is influenced by urea hydrolysis. The incorporation of nutrient medium extracted from urea yeast is necessary to keep S. pasteurii in an active metabolic state [Sporosarcina sp. achieved 461% more unconfined compressive strength (UCS) and 120% more calcium carbonate content than the bio-cement generated by S. pasteurii DSMZ 33 [Based on evidence in the literature, MICP has been intensively explored using different species of microorganisms to improve the compressive strength of cement composites such as mortar and concrete. ic state . It shouic state . Jonkersic state  reportedic state . In anotic state . Interes DSMZ 33 . These fS. pasteurii in a concentration of 105 cells mL−1 enhanced the compressive strength of concrete by 22% (it increased from 24 to 28 MPa) [5 mL−1 cells for self-compacting concrete with rice husk ash used as partial cement replacement. After the concrete cubes with 10% silica fume as a partial cement replacement were treated by S. pasteurii, the treated cement samples were tested to have an average 28-days compressive strength increase from 36 to 40 MPa at a bacteria concentration of 105 cells mL−1 in comparison to the untreated ones [S. pasteurii at cell concentrations of 106 cells mL−1, the compressive strength of lightweight aggregate concrete was noticed to improve by 20% [S. pasteurii could improve the properties of recycled fine aggregates (RFAs) of mortars due to adequate calcium carbonate precipitation on the mortar surfaces. The improved quality of RFA led to an increase in compressive strength of the mortars. It should be noted that sand stabilized with cement or geopolymer followed by MICP treatment led to a considerable increase in the compressive strength and stiffness due to the synergistic effects between chemical and microbial cementation [The results of the tests of a published study indicated that the inclusion of  28 MPa) . However 28 MPa)  reportede by 20% . For thee by 20% . Other te by 20%  found thentation .Bacillus bacteria are recognized as Gram-positive bacteria that can induce a binder filling material  precipitation) to improve the strength and durability of concrete. It has been reported that cell walls of Bacillus subtilis are capable of mediating MICP, thus forming CaCO3 and resulting in a 15% improvement in concrete compression resistance [B. subtilis had no positive effect on the compressive strengths of concrete. Mondal and Ghosh [B. subtilis-treated concrete at three bacterial cell concentrations, namely, 103 cells mL−1, 105 cells mL−1, and 107 cells mL−1. The highest strength improvement of the concrete was only recorded after treatment with a bacterial cell concentration of 105 cells mL−1. However, a separate study revealed that the values of compressive strength of B. subtilis-treated lightweight aggregate concrete samples with and without steel fiber  were slightly reduced by comparison to those of control concrete samples [Bacillus megaterium cells of 30 × 105 CFU mL−1 [B. megaterium showed a slightly higher compressive strength than those treated with B. subtilis.sistance . On the nd Ghosh  investig samples . AnotherCFU mL−1 . The incCFU mL−1 , concretB. subtilis, which were then added directly to induce bio-cementation on cement mortars. The increase in temperature, relative humidity, and wind speed led to higher compressive strength, while the increase in exposure time to sunlight reduced the compressive strength of bio-cement mortars. Zhang et al. [Bacillus halodurans improved the compressive strength of engineered cementitious composites. Shanmuga Priya et al. [Bacillus sphaericus. The inclusion of Bacillus aerius in concrete with 10% rice husk ash as partial cement replacement resulted in an improvement of compressive strength from 36 to 40 MPa [B. megaterium demonstrated a strength improvement up to 40% with a fly ash content of 10% as partial replacement of cement [Bacillus pseudofirmus was applied to modify recycled concrete aggregates using a bio-deposition method. The CO2 produced by the respiratory metabolism of B. pseudofirmus was used to produce calcium carbonate through MICP, leading to increased concrete compressive strength [Bacillus sp. CT5 for concrete treatment [5 cells mL−1 [It has been proven that curing conditions, such as temperature, relative humidity, wind speed, and sunlight exposure duration could affect the strength of bio-cemented mortars . The bacg et al.  have dema et al.  reportedf cement . Bacillustrength . A signireatment . A studylls mL−1 . The comBacillus was also reported in several published studies. Ghosh et al. [Shewanella species) in mixing water. The highest increase of 25% in 28-day compressive strength of cement mortar was achieved with an addition of 105 cell mL−1 bacterial concentration. The strength improvement was attributed to the growth of filling material in the form of calcium carbonate in the pores of the cement–sand matrix. Bio-OPC cement samples have been reported to be produced by deposition of bacterial calcium carbonate on cementitious materials [Exiguobacterium mexicanum isolated from seawater could improve the compressive strength of concrete by 24%. Approximately a 10% increase in concrete compressive strength was observed with the incorporation of alkaliphilic/alkali-tolerant bacteria in silica fume concrete at 28 days [The effect of bio-cementation on construction materials using bacteria other than h et al.  noted thaterials . In a staterials , a soil aterials  reported 28 days . Alkali- 28 days . Another 28 days  and coul 28 days ,52. ThesBacillus bacteria in cement composites. In addition to bio-cementation, the robustness of the cement composites was further enhanced with the inclusion of raw materials such as steel fibers, rice husk ash, and silica fume. For microorganisms that do not produce urease, such as bacteria from the Shewanella species, the concentration of bacterial cells and the source of nutrients were found to have a significant influence on their calcium carbonate precipitation, resulting in filling and binding effects on the cement composites. However, further research is needed to examine other underlying factors that may induce bio-cementation on cement composites from the microorganisms.It can be summarized from S. pasteurii bacterial solution to sand by percolation. The percolation process was repeated before the molds were sealed to achieve full saturation for the bricks. The maximum compressive strength of the bio-bricks was discovered to be 2 MPa [The production process of bio-bricks from MICP is more sustainable than the current processes of energy intensive production of bricks, such as kiln firing and the utilization of cement for manufacturing bricks. In the study of Bernardi et al. , bio-bribe 2 MPa . Using tbe 2 MPa  created be 2 MPa  producedbe 2 MPa  was madebe 2 MPa  adopted S. pasteurii as a microbial agent has been improved with the inclusion of biopolymer (guar gum) [Bacillus mucilaginous bacteria through MICP ranged from 8 to 16 MPa, and the strength increased with an increased lime/steel slag ratio [Bio-brick compressive strength with uar gum) , and theuar gum) ,58. Figuuar gum) . It was uar gum) , recycleuar gum) , and steuar gum) ,62 were uar gum) . It was ag ratio . Carboniag ratio . These fIt can be summarized from Aspergillus niger can effectively overcome the leaching of heavy metals from concrete incorporating waste foundry sand [Aspergillus spp. isolates could be used to treat waste foundry sand [Penicillium chrysogenum CS1 increased the compressive strength of a sand column by 1.8 MPa in a fungal mineralization process. Based on the compressive strength achieved, it can be deduced that the fungus has a good potential to be used for the production of bricks.Fungi have great potential for the extraction or removal of heavy metals . It has dry sand . In addidry sand . Concretdry sand  revealedTrichoderma reesei spores had a great potential for healing cracks, because they have grown well in the hyphal mycelium with the precipitation of concrete crystals and calcites were clearly observed [Aspergillus nidulans could grow in concrete slabs surviving in a high pH environment caused by the leaching of calcium hydroxide from concrete, and this promoted the precipitation of calcium carbonate [Jin et al.  noted thobserved . A studyarbonate . More reCandida ethanolica could be used for the surface coating of concrete with polluted sand as a fine aggregate. At an initial optimal pH of 8.5, a calcium oxide concentration of 60 g L−1 and a concentration of fungal cells of 107 cells mL−1, concrete cubes treated with the fungi were tested to have an average 28-day compressive strength of 32.2 MPa, which is 6.27% greater than that of the untreated concrete cubes . The comparison was made to justify the advantage of HAP over CaCO3, which was known to be dissolved under low pH water solution. HAP was shown to have a lower solubility and dissolution rate compared to CaCO3. It has also been proven to have a higher resistance to acid attack by comparison to CaCO3. Results of water absorption for the CaCO3-treated bricks were obtained from tests based on a single treatment method, multi three-day treatment method, and multiple one-day treatment method  media by close monitoring of up to 28 days. Water absorption tests were performed to measure the resistance of bio-calcified bricks to water penetration, which could affect their strength performance. The results of the study indicated that water absorption of the bio-calcified bricks with S. pasteurii and (OptU) media was reduced by 48.9%, and that an addition of nutrient broth (NB) in the media caused their water absorption to reduce by 19.95% compared to that of the control bricks. It can be interpreted from these results that the bio-calcification effect of S. pasteurii in OptU media was greater than that of S. pasteurii with NB. This could be related to the reduced water absorption of the bricks due to their increased durability and longevity after treatment with S. pasteurii in the OptU media.Raut et al.  studied 3 precipitation, which filled up the pore spaces of the brick aggregate and simultaneously worked as a particle binding agent in the concrete. Furthermore, it was realized that the longer bacterial incubation period could be related to the greater reduction in the water absorption due to the higher number of bacteria grown for calcium carbonate precipitation in concrete.Manzur et al.  investigB. pseudofirmus in the respiration process. This process differs from the conventional method of precipitation of CaCO3 using urea hydrolysis. The motivation of the RCA study was that it is beneficial to reuse demolished concrete from construction sector as mortar aggregate because disposal of the demolished concrete can add to the accumulation of waste in landfill, thus degrading the environment. Based on the results of the study, the water absorption values of untreated RCA (U-RCA) mortars were found to be higher at 12.3% for 0.5 water to cement (w/c) ratio, and 7% for 0.35 w/c ratio, respectively, compared to those prepared with the natural aggregate (NA), which were 8.3 and 5% at the respective water to cement ratios  of bio-cemented construction materials provided an in-depth understanding on the binding mechanism of the particles within the materials. On the other hand, a review of chemical compositions of bio-cemented construction materials provided information on the mechanism of MICP to solidify them. In this regard, literature discoveries from X-ray diffraction (XRD) and energy dispersive X-ray (EDX) of materials are important for providing evidence on the chemical constituents that characterize their bio-cementation process. Detailed analyses and discussions of the literature related to these aspects are presented in this section.Paenibacillus bacteria. In their work, the binding effect of sand particles with bio-cement from the bacteria was evaluated based on the number of times the bio-cement was sprayed on the sand particles. For the bio-cementation of the sand particles, the spraying process was implemented up to seven times. The mechanical properties of bio-cemented sand materials improved with an increase in the number of spraying time, because microstructures of the materials became denser as a result of the bio-cementation process which effectively clogged their void spaces. Zhan and Qian  researchS. pasteurii was used to produce bio-composite cement with an ultimate aim of enhancing the mechanical properties of the bio-sandstone through injections. Microstructures of the bio-sandstone, which have been subjected to different numbers of bio-composite cement injections, are shown in A similar trend could be observed in the microstructures of bio-sandstone improved with up to six injections of bio-composite cement in the published work of Yu et al. . S. pastS. pasteurii. These were calcium acetate, calcium nitrate, and calcium chloride. The microbial mortars were produced using grouting technology of pumping three batches of bacterial solution (S. pasteurii and culture medium), fixative solution , and nutrient solution . Scanning electron micrographs of microbial mortars with all three types of calcium source are depicted in 3 [θ = 26.223°. This confirmed the presence of aragonite as the predominant calcium carbonate crystals in micrographs of the acetate sample in According to Zhang et al. , the effted in 3 . The XRDFurther microstructural evidence on bio-cementation can be observed in the micrograph of MICP-treated bio-bricks shown in 5 CFU mL−1 of water under MICP. Without bacterial treatment, the morphology of the silica fume concrete was predominated by calcium silicate hydrate (CSH) crystals which significantly reduced the pores of the concrete  result as indicated in The calcium carbonate mineral could also be identified by the morphological result of fungal surface treatment of concrete cube by g et al. . A fossiAfter reviewing B. pseudofirmus could induce calcium carbonate precipitation, which offered an eco-friendly solution to repair concrete wall micro-cracks of a nuclear structure instrumented under a pressure of 500 kPa. It must be noted that the ability of bacteria to survive in a highly alkaline concrete environment during the formation of calcium carbonate crystals in concrete implies that the presence of the bacteria did not have a negative impact on the hydration reaction [In construction practice, Lors et al.  found threaction . The micreaction  revealedS. pasteurii has been identified as the most studied microorganism for MICP on construction materials due to its high urease activity, growth rate, and reactivity to a source of calcium. The calcium carbonate precipitated by MICP served as a filler and cementing agent that minimized the porosity of construction materials. In addition to MICP, the inclusion of additional materials such as rice husk ash, silica fume, fly ash, and chromium slag as partial cement substitutes in construction materials could further reduce their porosity. It was the reduction in porosity of construction materials by MICP that led to the improvement of their mechanical properties. In this regard, MICP resulted in enhanced compressive strength and reduced water absorption of construction materials through crack repair, surface treatment, and bonding effects. Scanning electron micrographs and XRD results of bio-cemented construction materials from the literature studies revealed the presence of calcite, which is the most stable calcium carbonate mineral precipitated by microorganisms in the MICP. Despite the positive results in the literature, further research should be carried out to investigate the fire resistance of bio-cemented construction materials in order to establish a complete understanding of their fire durability. With the advancement of the research, the prospect of commercializing bio-cementation in construction materials seems promising.It can be concluded from the critical review of the articles that microorganisms have played an important role in bio-cementation on construction materials including concrete, brick, and mortar. The effectiveness of microorganisms in inducing bio-cementation depends to a large extent on the microbial type, as well as the optimal conditions of MICP.


Although the current scientific literature does not support the routine use of antibiotics after dental extractions, patients believe that these drugs offer clear benefit during the postoperative period. The main objective of this study was to describe patient perception of the need for antibiotics after routine tooth extraction and to assess knowledge about the benefits and adverse effects of antibiotic therapy.A cross-sectional study was carried out. A total of 452 participants requiring tooth extraction and seen in the Dental Clinic of the University of Barcelona  were given a specific questionnaire on the need for antibiotics after dental treatments or diseases, and on their benefits and adverse effects. Descriptive bivariate and multivariate (logistic regression model) analyses were performed. p<0.05). According to the respondents, the main advantage of antibiotics was the reduction of infection rates, while the most frequently mentioned adverse events were allergic reactions, diarrhea and nausea or vomiting.Of the 452 participants, 185 (40.9%) were men and 267 (59.1%) were women, with a mean age of 35.2 ± 15.9 years. Most of the patients (76.6%) expected to take antibiotics after tooth extraction. A higher level of education, older age and knowledge about bacterial resistances were inversely correlated to the perceived need for antibiotic treatment (Most patients think that antibiotics are necessary after routine dental extraction to prevent postoperative infection. Younger patients with a low educational level and who are unaware of the problem posed by bacterial resistances seem to be more supportive of antibiotic prophylaxis. Most respondents are familiar with the main benefits and adverse effects of these drugs. Key words:Antibiotic, microbial drug resistance, tooth extraction, oral surgery, survey, postoperative wound infection. Many professionals routinely prescribe antibiotics after elective surgical procedures . HoweverThe widespread use of antibiotics has led to an increase in microbial resistances. The latter are now considered to be a global health problem, since they raise the biological cost for patients  and constitute an economic burden for national healthcare systems -19. IndeA Spanish national health survey comprising 19,514 individuals over 16 years of age found 17.7% of the respondents to report self-medication with antibiotics . Women, Insufficient knowledge about the indications of antibiotic treatment has also been related to self-medication . In thisIn view of the above, and given that many patients might believe that antibiotics are needed to prevent complications after simple dental procedures, a survey on patient knowledge about antibiotic use after dental extraction could be useful for establishing educational strategies focusing on the correct use of such drugs. Accordingly, the main objective of the present study was to assess patient perception regarding the need for antibiotics after routine dental extractions in a university dental hospital. The secondary aim was to describe patient knowledge of the main benefits and adverse effects of antibiotic therapy.A cross-sectional study was made involving consecutive patients over 18 years of age seen in the Dental Clinic of the University of Barcelona  during 2019 for routine tooth extraction. Patients referred to the hospital for other surgical procedures, as well as individuals suffering from mental disorders that might complicate understanding of the study, were excluded. The study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement .The study protocol was approved by the local Institutional Review Board (protocol number 1/2019), and all individuals willing to participate signed the corresponding informed consent. The Declaration of Helsinki guidelines on research involving human subjects were followed throughout the study.A specific 15-question survey, adapted from the questionnaire published by Boxx and Laskin , was useSample size calculation was made using the Stata / IC 15.1 package . A proportion estimation for a finite population of 3000 patients was performed, taking into consideration that 67% of the patients consider it necessary to take an antibiotic after tooth extraction (according to Boxx and Laskin (23)). A total of 452 subjects were required for an absolute accuracy of ± 4% and a 95% confidence level.Descriptive and bivariate statistics were calculated, and a logistic regression model was generated to detect variables associated to the need for antibiotic treatment, using the Stata / IC 15.1 package .A total of 452 patients (185 men (40.9%) and 267 women (59.1%)) with a mean age of 35.2 ± 15.9 years (range 18-83) answered the questionnaire.p=0.007), while knowledge about bacterial resistance was associated to a significantly lower perceived need for antibiotic treatment (p=0.009).Regarding specific questions, 347 of the 452 patient (76.6%) expected their dentists to prescribe an antibiotic after tooth extraction. Likewise, almost half of these patients  mentioned that if the professional did not prescribe an antibiotic, they would personally request such medication, and 56 subjects (18.7%) would even ask for a professional second opinion. The patients believed antibiotics to be necessary to prevent infections , to ensure faster recovery , to return to work or school earlier , or for no specific reason . Forty-one respondents didn’t know or didn’t answer (9.1%).Dental infections were considered an indication for antibiotic use by 401 patients (88.7%), while 240 participants (53.2%) expected an antibiotic to be prescribed if they suffered toothache. One hundred and one patients (28.9%) had medicated themselves at least once during their lifetime.Figure Sixty-five patients (14.4%) reported that they would request their physician to prescribe antibiotics to treat a cold. Lastly, most of the participants  were familiar with the concept of antibiotic resistance.The logistic regression model showed a lower educational level, younger age and unawareness of bacterial resistance to be significantly correlated to the perceived need for antibiotic prescription .The results of the present survey confirmed the hypothesis that patients have limited awareness concerning antibiotic use after routine tooth extractions. Approximately three out of every four patients expected their dentists to prescribe antibiotic treatment after dental extraction, mainly to prevent postoperative infections. The multivariate analysis showed that older patients with a higher educational level, and with some knowledge about bacterial resistances, made a more conservative judgment regarding the need for antibiotic treatment.Boxx and Laskin , in a siet al. (Self-medication with antibiotics has been a common practice in relation to illnesses of the upper respiratory tract. Interestingly, Grigoryan et al. , in a stet al.  (14.4% aet al. (Other publications have focused on overall self-medication. Dental problems are the most common problem for which pharmacists dispense medicines without a medical prescription . In factet al.  showed tet al. . On the et al. .The fact that the patients in our study exhibited a wide age range and a diverse educational background ensures the external validity of the results in the Spanish population. The outcomes of our study underscore the need to develop educational campaigns to increase the awareness of the general population towards the actual needs of antibiotic use, the associated adverse events and, most importantly, to contribute to reduce microbial resistances. Fortunately, public educational campaigns have been shown to be effective in changing attitudes and knowledge about antibiotic use and microbial resistances . In addiMost patients believe antibiotic issue to be necessary after routine tooth extraction to prevent postoperative infection. Younger patients, with a lower educational level, and who are not familiar with the concept of bacterial resistance seem to be more prone to self-medication.Although patient knowledge about the risks and benefits of antibiotic use is generally acceptable, the results of the present survey underscore the need to implement antibiotic awareness campaigns in order to reduce unnecessary antibiotic prescription after tooth extraction.


This paper presents results from experimental work on mechanical properties of geopolymer concrete, mortar and paste prepared using fly ash and blended slag. Compressive strength, splitting tensile strength and flexural strength tests were conducted on large sets of geopolymer and ordinary concrete, mortar and paste after exposure to elevated temperatures. From Thermogravimetric analyzer (TGA), X-ray diffraction (XRD), Scanning electron microscope (SEM) test results, the geopolymer exhibits excellent resistance to elevated temperature. Compressive strengths of C30, C40 and C50 geopolymer concrete, mortar and paste show incremental improvement then followed by a gradual reduction, and finally reach a relatively consistent value with an increase in exposure temperature. The higher slag content in the geopolymer reduces residual strength and the lower exposure temperature corresponding to peak residual strength. Resistance to elevated temperature of C40 geopolymer concrete, mortar and paste is better than that of ordinary concrete, mortar and paste at the same grade. XRD, TGA and SEM analysis suggests that the heat resistance of C–S–H produced using slag is lower than that of sulphoaluminate gel  produced using fly ash. This facilitates degradation of C30, C40 and C50 geopolymer after exposure to elevated temperatures. Clearly)AlSiO4) , 50% [51)AlSiO4) ,32,52 af2), C–S–H, brownmillerite and β-C2S, and the XRD patterns of OP-C40 had no significant change after 200 and 400 °C exposure. However, the peak related to C–S–H disappeared and the significant reduction of portlandite significantly decreased after 600 °C exposure, while the intensities of peak related to β-C2S was increased, which is a by-product of C–S–H decomposition [2 decomposition was clearly detected as well. The calcite (CaCO3) could be also captured at 800 °C. It may be assumed that CaO formed by Ca(OH)2 decomposition reacts with CO2 present in the furnace and forms CaCO3 [On the other hand, for ordinary paste, position ,53. Aftems CaCO3 . These rms CaCO3 ,45,53,54The SEM results of geopolymer and ordinary paste are shown in (1)Different from ordinary concrete, mortar and paste, after 28 days, the compressive strength of geopolymer concrete, mortar and paste still increases significantly and the strengths of C40 geopolymer concrete, mortar and paste are significantly higher than that of C40 ordinary geopolymer concrete, mortar and paste.(2)The compressive strength of C30, C40 and C50 geopolymer concrete, mortar and paste displays increment initially followed by a gradual reduction, and finally reached a relatively consistent value with the increase of exposure temperature, while the compressive strength of C40 ordinary concrete, mortar and paste remained approximately invariant before 400 °C, and then decreased rapidly. With the increase of concrete strength grade , the elevated temperature resistance of geopolymer concrete, mortar and paste gradually decreases. In addition, the elevated temperature resistance of C40 geopolymer concrete, mortar and paste is better than that of ordinary concrete, mortar and paste of the same grade.(3)At the same heating temperature, GC-C30, GC-C40, GC-C50 and OC-C40 basically demonstrated the phenomenon that compressive strength retention has the best performance, which is followed by the splitting tensile strength, and flexural strength proved to be the lowest. The results indicated that the susceptibility of flexural strength, splitting tensile strength and compressive strength to elevated temperature decreased in turn for both geopolymer and ordinary concrete.(4)XRD, TGA and SEM results showed that with the increase of concrete strength grade, the content of C–S–H formation in geopolymer increases, while the content of aluminosilicate gel, quartz and mullite decreases. Moreover, the heat resistance of C–S–H produced by slag is weaker than that of sulphoaluminate gel  produced by fly ash, which is the main reason for the decrease of C30, C40 and C50 geopolymer in turn after exposure to elevated temperatures.The present study investigated the mechanical properties of fly ash and slag blend based geopolymer concrete, mortar and paste after elevated temperature exposure. Further, XRD, TGA and SEM were conducted to investigate the influences of mineralogical and micro-structural changes on the mechanical properties of geopolymer. Conclusions can be drawn from the experimental results and analysis presented in this paper.


With steel fiber and basalt fiber volume dosing serving as variation parameters, a total of 200 d cycles of acid rain corrosion cycle tests were conducted on fiber concrete in this study. We selected three durability evaluation parameters to assess the degree of damage deterioration on fiber concrete, used scanning electron microscopy, mercury intrusion porosimetry, and a dimensional microhardness meter to analyze the concrete micromorphology, and established a GM-Markov model for life prediction of its durability. Results reveal that the acid rain environment is the most sensitive to the influence of the relative dynamic elastic modulus evaluation parameter, and concrete has specimens that show failure damage under this parameter evaluation. Incorporation of fibers can reduce the amount of corrosion products inside the concrete, decrease the proportion of harmful pores, optimize the mean pore-size, and significantly improve the resistance to acid rain attack. Concrete with 2% steel fiber and 0.1% basalt fiber by volume has the least change in durability damage, and the predicted service life by GM-Markov model is 322 d. In recent years, with the dramatic increase in emissions of nitrogen oxides and sulfides, acid rain pollution has become one of the important environmental issues in the world today, and it shows a continuous expanding trend of the affected area. Research reports indicate that over 100 billion yuan of annual losses in China is caused by acid rain problems, with the largest proportion of economic losses done by acid rain corrosion of construction materials such as concrete ,3,4.+ and expansion damage caused by SO42−. Xu et al. [At present, researchers have conducted some research on the mechanism of acid rain corrosion of concrete and the deterioration of concrete performance after corrosion, and proposed improvement measures to reduce the corrosion of concrete by acid rain. The improvement measures mainly lie in two aspects: on the one hand, the incorporation of mineral admixtures can improve the corrosion resistance of concrete to acid rain. Shi et al.  studied u et al.  simulateu et al.  found thu et al.  used meru et al.  believesu et al. , Koksal u et al. , Ibrahimu et al. , etc., iIn order to ensure the safety of concrete materials in an acid rain corrosive environment, it is especially important to judge whether concrete can complete the intended function within the design reference period. The life prediction of concrete durability has become a hot topic of research in the civil engineering industry ,17,18,192/kg was also utilized, and the chemical components of the cementitious material are shown in 3 and mud content of 0.5%. The fine aggregate was made of Lanzhou Anning River sand, which was medium sand with a fineness modulus of 3.18 and an apparent density of 2581 kg/m3. The water used was tap water. The steel fiber (SF) and basalt fiber (BF) were provided by Shanghai Chemical Building Materials Factory , and the main physical properties are detailed in P.O 42.5 grade ordinary silicate cement  with good stability was used in this study. Class II fly ash  with a specific surface area of 440 m3 were prepared. Each group of specimens was placed in a curing chamber at a temperature of 30 ± 2 °C and with a relative humidity of 80% for 28 days. Then, the test specimens were transferred into the indoor cyclic test chamber ZC-2512, as shown in According to the ratios given in 1, relative mass evaluation parameter ξ2, and relative dynamic elastic modulus evaluation parameter ξ3 for concrete durability under different acid rain corrosion ages, respectively. Each evaluation parameter is shown in Equations (1)–(3):cn and fc0 are the compressive strengths (MPa) after n test cycles and at the initial stage, respectively. mn, mo denote the mass of the specimen (kg) measured after n test cycles and at the initial stage, respectively. vn, v0 denote the ultrasonic velocity (m/s) measured after n test cycles and at the initial stage, respectively. When ξ is less than 0, the concrete is considered to have failure damage, and when ξ is between 0 and 1, the specimen is considered to have damage deterioration.In order to effectively track the durability damage deterioration pattern of fiber reinforced concrete, the data of concrete specimens were collected at 20-day intervals. Similarly, the GB/T 50476-2019 outlines three conditions for concrete failure after spray-light cycles. When the compressive strength is reduced by 25%, the mass is reduced by 5%, or the relative dynamic elastic modulus is reduced by 40%, a condition is fulfilled, indicating that the test specimen has reached durability failure. In this test, the number of spray-light cycles that the fiber concrete withstood was used to express its resistance to acid rain environmental corrosion. The YH-300 electro-hydraulic servo press  was used for the test of compressive strength. The NM-4A ultrasonic tester  was used to test the sound velocity. A high-precision electronic balance was utilized to test the mass. In addition, in order to facilitate comparison of the damage deterioration rates of fiber concrete under acid rain corrosion in different test conditions, the test data were normalized and evaluated on the basis of the compressive strength evaluation parameter ξ3, which was metal sputtered before the test. SEM testing was performed using a Zeiss Sigma 300 field emission electron microscope. Mercury porosimetry specimens were made by cutting the test sample with volume size not larger than 0.5 × 0.5 × 1 cm3, and placed in anhydrous ethanol to terminate hydration for 48 h. The AutoPoreIV9510 mercury piezometer  was used for the mercury intrusion porosimetry test. Each microhardness test specimen was cut in the middle using a cutting machine to create a section with a thickness of 20 mm and then polished. The HVS-1000A Vickers microhardness tester  was used to test the microhardness values at different locations from the edge of the aggregate by hitting the points sequentially from the side of the aggregate toward the cement matrix. Seven hitting locations were established, with the first point being 10 µm from the edge of the aggregate, the next two points being 20 µm apart, and the last point being 130 µm from the edge of the aggregate. The microhardness value at each point location was taken as the average of five hits at the same distance from the edge of the aggregate at the arc location of the point.Some concrete specimens were transported back to the laboratory at the end of the 200-day test cycle to reveal the damage deterioration mechanism of fiber concrete in the acid rain environment. Samples were made, and the damage of fiber concrete was observed using SEM, mercury intrusion porosimetry, and microhardness. For the preparation of fiber concrete SEM specimens, the fiber concrete was crushed and the cement mortar pieces were taken as samples, and the sample size was approximately 1 × 1 ×1 cm1 was greater for the fiber concrete specimens than for OPC. The S2B0.1 group, in particular, reached the peak of ξ1 at 40 days with 122.07%, which was found to be the largest increase. After 200 corrosion cycles, the compressive strength of each group of specimens was damaged to varying degrees. In the OPC group, ξ1 decreased to 15.40% with the most severe impairment. By contrast, the damage of the fiber-doped specimen ξ1 was relatively light. The degree of damage in descending order was S2B0.2 > S1B0.2 > S1B0.1 > S2B0.1. Two main factors explained the increase in the compressive strength of concrete in the early stages of corrosion by the acid rain environment. First, the specimen continued to hydrate in the corrosion solution. Second, the corrosion products that were generated in the early stages filled the internal pores of the concrete, thereby making the concrete increasingly dense and causing the compressive strength to rise. However, as the age of corrosion increased, the large number of generated expansions produced microcracks by extrusion within the concrete, thus causing a decrease in compressive strength. However, as the corrosion age increased, the SO42− in acid rain solution gradually migrated into the concrete, and when the internal pores did not have enough space to accommodate the expansion products, micro-cracks formed quickly, resulting in a decrease of the compressive strength [1 corrosion age variation curve of the concrete specimens mixed with fibers was more stable than that of OPC.With the increase in the number of spray-light corrosion cycles, the change curve of compressive strength evaluation parameters for each group is shown in strength . Thus, t2 of fiber concrete with acid rain corrosion time. The data sets showed a synchronous upward change at 20 days, followed by a fluctuating change with the increasing age of corrosion ξ2 and a synchronous decrease at 160 days. The highest mass loss rate was observed in the OPC group at 200 days when ξ2 was 70.4%. The mass loss of the concrete specimens mixed with fibers was not significant, with only 5% of ξ2 of S2B0.1 being lost. This result indicated that the incorporation of SF and BF could significantly improve the mass loss inhibition ability of concrete. In the middle of the test, ξ2 for each group of data fluctuated because of the dynamic changes in the filling effect of corrosion products and the destructive effect of corrosion expansion crystals. With the passage of time, the filling effect of corrosion products gradually transformed into expansion damage. The specimen surface began to show considerable peeling and slagging, and the macroscopic performance indicated that ξ2 began to decline. In addition, ξ2 of fiber concrete at 200 days was greater than ξ1, which may be due to the fact that the physical crystallization destruction ability of spray-light has not yet caused the fiber concrete to exhibit quality loss behaviors, including dissolution precipitation of cementitious materials and aggregate shedding.3 of fiber concrete are shown in 3 of OPC rose slowly at the early stage of corrosion and decreased rapidly after 40 days. ξ3 decreased to 0 at 180 days when the concrete material’s durability failed. Relative to that of plain concrete, ξ3 improved to different degrees for each group of specimens of fiber concrete. At 200 days, the ξ3 sizes of the fiber concrete specimens were S2B0.1 > S2B0.2 > S1B0.1 > S1B0.2. ξ3 of S1B0.2 dropped to 0, which reached the damage criterion. The reason for this may be due to the increase in the number of cycles, as the spray-light-generated power drove the migration of corrosion ions into the concrete, and constantly consumed the gelatinous C-S-H and C-A-H, resulting in the internal pore wall of the concrete to easily crack under expansion stress. Moreover, the propagation speed of ultrasound weakened, and the ξ3 value decreased. SF and BF worked together with C-S-H to form a fibrous mesh bonding structure to enhance the adhesive properties between the cementitious materials and the aggregates and share the expansion stresses generated within the concrete caused by acid rain corrosion. These conditions led to the inhibition of the decrease in dynamic elastic modulus. By contrast, the increase of the SF admixture caused the ξ3 of concrete to rise under the same BF admixture. The SF obviously exerted a great influence on the improvement of the relative dynamic elastic modulus of concrete. Poorsaheli et al. [1, ξ2, and ξ3, S2B0.1 was found to be the best mixture proportion for this test. The order of the magnitude of sensitivity of the three durability evaluation parameters of fiber concrete under acid rain corrosion was ξ3 > ξ1 > ξ2. This result is explained as follows: at the end of the test, durability failure was noted in the specimens with ξ3 of 0 in each group; those with ξ1 and ξ2 still exceeded 0.The experimental data for the relative dynamic elastic modulus evaluation parameter ξi et al.  concludeAccording to Dong’s study , concretA GM prediction model is established, and let the original data series be as follows:(1)(t) is considered as the 1-AGO generation series of X(0)(t) as follows:One of the important data operations in GM model is the accumulative generating operation, abbreviated as AGO. Then, X(1)(t), where Z(1)(t) is calculated as follows:Define This formula leads to the whitening differential equation for the GM model, as shown in Equation (7).The GM prediction model and GM prediction value can be obtained by substituting the solved coefficients a and u into Equation (7) and solving the whitening differential equation as follows:(o)(t) is obtained after absolute value transformation.The residual prediction model is then established. As a result of the existence of the negative values of the original values of the residual ε, the residual εThen, the residual series can be created as follows:By repeating steps (5) to (10), the residual prediction model and the residual prediction values are obtained as follows:ij is the transfer probability from state i to state j; Mij is the transition time from state i to state j, and Mi is the amount of data belonging to the i-th state.By analyzing the regularity information in the residuals, the Markov transfer matrix can be established to specify their states: state 1 when the residuals are positive and state 2 when they are negative. The state transfer probabilities can be obtained according to the positivity and negativity of the states as follows: The state probability transfer matrix can be derived from the state transfer probabilities as follows:The final GM-Markov model and the predicted values are obtained as follows:r as the durability evaluation parameter. The analysis of Equation (3) shows that when it is lower than 0.6, the concrete specimen is considered to have failure damage. In this section, the relative dynamic elastic modulus damage degradation process of OPC is selected as the input data and the GM-Markov model of OPC under acid rain environment is developed as follows:From the durability test results in The specific prediction results obtained are detailed in After confirming that the GM-Markov model had a high prediction accuracy, the remaining life of each group of specimens was predicted by the model to further understand the damage deterioration trend of fiber concrete. The results are shown in In this paper, the durability damage deterioration law of fiber concrete under acid rain corrosive environment is investigated by both macroscopic and microscopic tests, and the service life is predicted by using a GM-Markov model. Based on the tests and analysis, the following conclusions can be drawn.(1)Incorporation of steel fibers and basalt fibers can play an inhibiting role in the deterioration of damage to concrete under the effect of acid rain corrosion. The best effect is achieved when the volume dose of SF is 2% and the volume dose of BF is 0.1%.(2)The microscopic test results show that the fibers share the expansion stress caused by corrosion products to a certain extent, improve the pore structure, reduce the thickness of ITZ, make the concrete micro-structure more dense, and enhance the resistance to acid rain corrosion.(3)The GM-Markov model has a high prediction accuracy and can effectively predict the damage deterioration trend of fiber concrete, which provides a good theoretical basis for the repair and reinforcement of concrete in acid rain areas.