Heroin pipe distribution may encourage people who use heroin (PWUH) to transition from injecting to smoking heroin, reducing harms associated with injection drug use. A syringe services program (SSP) in Seattle, Washington, led by people who use drugs developed a heroin pipe distribution program.We conducted a pretest–posttest quasi-experimental study to evaluate the impact of heroin pipe distribution on drug consumption behaviors among PWUH between March and December 2019. SSP clients were surveyed during three weeklong timepoints before and four weeklong timepoints after heroin pipe distribution. Primary outcomes were change in proportion of SSP clients who exclusively injected heroin, exclusively smoked heroin, and both injected and smoked heroin in the past seven days comparing the pre- and post-intervention periods.p = 0.02), while the proportion of respondents who both injected and smoked heroin was higher . Just under half  of respondents who used heroin during the post-intervention period used a heroin pipe obtained from the SSP, of which 34% (37/110) reported heroin pipe distribution had reduced their heroin injection frequency. Self-reported hospitalization for a pulmonary cause was not associated with using a heroin pipe.Across the seven observation timepoints, 694 unique respondents completed 957 surveys. Multiple responses from a single respondent in a given period were collapsed, resulting in 360 pre-intervention and 430 post-intervention records. Heroin use was reported in over half of pre-intervention  and post-intervention records . Compared to pre-intervention behaviors, the proportion of respondents who exclusively injected heroin was lower after the start of heroin pipe distribution (32%, 80/251 vs 43%, 86/201, The proportion of SSP clients who exclusively injected heroin was lower after implementation of heroin pipe distribution. Randomized studies with longer follow-up are needed to investigate whether heroin pipe distribution reduces heroin injection and improves health outcomes associated with drug use. Limited intervention exposure, loss to follow-up, and pipe availability from other sources pose methodological challenges to evaluations of route transition interventions in community settings. This pilot highlights the potential for organizations led by people who use drugs to develop, implement, and evaluate novel public health programming.The online version contains supplementary material available at 10.1186/s12954-022-00685-7. People who use heroin (PWUH) have increased morbidity and mortality compared to the general population . A syndeBecause smoking heroin does not injure the skin or introduce non-sterile equipment into blood or tissue, this method of consumption does not entail the same risk of blood-borne infections or SSTI compared to injection. While similar pharmacological effects can be achieved by smoking or injecting heroin, peak plasma concentrations are 2–4 times lower when heroin is smoked, which may reduce risk of lethal opioid overdose , 14. ProThe potential for route transition interventions (RTIs) to improve health outcomes among people who use drugs (PWUD) was first identified in the 1990s . Since tA harm reduction service provider in Seattle, Washington, began offering heroin pipes to clients at a syringe service program (SSP) in 2019. This heroin pipe distribution program was developed at the request of SSP clients who expressed interest in heroin smoking as an alternative route of consumption that avoids difficulties in obtaining intravenous access and had a lower perceived risk of opioid overdose. We conducted a pretest–posttest quasi-experimental study to evaluate the impact of this novel harm reduction intervention on drug consumption behaviors and health outcomes among PWUH. We also aimed to measure potential harms associated with pipe distribution.This quasi-experimental study used a one-group pretest–posttest design with multiple measurement timepoints. We conducted three weeklong pre-intervention observations at months 0, 1, and 2, and four weeklong post-intervention observations at months 4, 5, 6, and 9. The earliest pre-intervention timepoint was in March 2019, and latest post-intervention timepoint was in December 2019. The intervention was implemented at month 3 (June 2019). Three pre-intervention and four post-intervention timepoints were used to reduce threats to internal validity, including history , instability , and maturation .This study was conducted at a single SSP site in Seattle, Washington, operated by The People’s Harm Reduction Alliance (PHRA), a community-based organization (CBO) that provides harm reduction services to PWUD. This SSP offers an array of harm reduction services to PWUD four days a week, including syringe distribution and disposal, naloxone training and distribution, and medication-assisted treatment for opioid use disorder. In the year prior to this study, 2.5 million syringes were distributed through this SSP in more than 17,000 client encounters. PHRA has also distributed crack cocaine pipes since 2010 and methamphetamine pipes since 2015.Study participants were recruited at the SSP site during service hours. Any PHRA client who accessed services during a pre-specified weeklong pre-intervention or post-intervention observation timepoint was offered the opportunity to be screened for eligibility to complete a survey. Eligibility criteria included being a PHRA client, ability to complete surveys in English, being 18 years old or older, and ability to provide informed consent. Participants could only complete one survey during each weeklong observation timepoint.We intended to sample SSP clients during each weeklong observation timepoint as well as enroll a longitudinal cohort of SSP clients to be followed across timepoints. Therefore, before beginning a survey all participants were asked to provide a unique 6-character code comprised of their first and last initials, the first two letters of their mother’s first name, and the day of the month on which they were born. The code was used to prevent duplicate surveys from the same individual within a single timepoint and to track an individual’s responses across separate timepoints. Once enrolled, participants who opted to provide contact information were sent email or text message reminders prior to subsequent observation timepoints to promote retention.The intervention was the implementation of a heroin pipe distribution program at an SSP. This program included the provision of pipes designed to smoke heroin and related education material. A total of 35 heroin pipes were available for distribution each day the SSP was in operation. Heroin pipes were distributed on a first-come first-served basis, and each client received a maximum of one pipe per day. Educational material described how the pipe could be used to smoke heroin as well as alerting users to the continued risk of opioid overdose , a grassroots coalition of PWUD. Focus groups with PHRA clients and USU members who inject and smoke heroin were conducted between May and August 2018 to evaluate a prototype design. Pipe shape and size were then refined based on participant feedback. The final version of the intervention pipe was manufactured by Pegasus Industrial Specialties Inc.  sociodemographic characteristics, (2) drug consumption behaviors, (3) high-risk injection behaviors  (4) health outcomes associated with drug use , (5) the HCV care continuum, and (6) social harms associated with crack cocaine or methamphetamine pipe distribution . Post-intervention surveys also collected data on utilization and perceived impact of the heroin pipe distribution program and potential harms associated with heroin pipe possession. Pre- and post-intervention survey forms are included in Additional file  sociodemAll surveys were administered verbally by volunteer research project staff. Survey forms were hosted on REDCap, a web application for designing and managing online surveys, and participant answers were input into online survey forms using a mobile device . Draft vAs the intervention was a pilot project that had not been previously studied, an effect size could not be estimated, and therefore, no pre-specified sample size was set prior to recruitment. The final sample size was determined by the total number of eligible SSP clients who completed at least one survey.Primary outcomes were change in the proportion of SSP clients who exclusively injected heroin, exclusively smoked heroin, and both injected and smoked heroin in the past seven days as well as median number of weekly intravenous (IV) and intramuscular (IM) heroin injections between the pre- and post-intervention time periods. Secondary outcomes included changes in the proportion of SSP clients who used heroin by any route and reported syringe sharing, syringe reuse, and public injection in the past seven days as well as the proportion of SSP clients who used heroin and reported opiate overdose, SSTI, and hospitalization for any cause in the past 30 days.Sociodemographic characteristics included age, gender, race, income, and housing status. Income was measured as a continuous variable and a binary variable (no income vs > $0 average monthly income). At each survey timepoint, participants were asked where they have been living most of the time during the past 30 days, and responses were categorized as housed (my own home/apartment or the home/apartment of friends/family) or unhoused . Participants were also asked to report the gender of sexual partners during the past year, and we considered participants who reported being cisgender men and having sex with men in the prior year as men who have sex with men (MSM). We measured and reported MSM status in this study because MSM who inject drugs account for the majority of new HIV diagnosis among people who inject drugs in the Seattle area.All participants were asked if they had ever injected any drug and, if so, age when they first injected. We derived a measure of length of injection in years using the difference between the participant’s current age and age of first reported injection. Past month injection was assessed among those reporting lifetime injection. Syringe sharing, syringe reuse, and public injection in the past 30 days were assessed at each survey timepoint.Participants were asked which drugs they had used in the past seven days , heroin and cocaine/crack together ) and the route of administration for each drug used . Participants were then asked how many times they used each drug via each reported route of administration in the past seven days. Those who reported heroin use were asked if they had tried to reduce their heroin use in the past 30 days. During the post-intervention period, surveys also asked participants if having access to the heroin pipe intervention made them smoke or inject heroin more frequently, less frequently, or had no impact on their frequency of use.Surveys asked participants if they had an abscess, cellulitis, skin ulcerations, or been hospitalized in the past 30 days. Reports of an abscess, cellulitis, or a skin ulceration were combined into an SSTI measure. Participants who reported being hospitalized in the past 30 days were asked if they were diagnosed with infective endocarditis, an asthma or chronic obstructive pulmonary disorder exacerbation, pneumonia, or other lung infection during that hospitalization.During the post-intervention period, participants were asked if they had smoked drugs in the past 30 days using the heroin pipe designed by PHRA. Participants who used a heroin pipe were asked what drugs they had used the heroin pipe to smoke, total number of heroin pipes they received, and number of times they were unable to obtain a heroin pipe from PHRA because of limited stock in the past 30 days. Participants were also asked if they had been arrested in the past 30 days and whether their arrest was a consequence of possessing a heroin pipe.We first described all unique survey respondents and compared sociodemographic characteristics and drug use behaviors of those who did and did not report using heroin during any survey timepoint. We then performed descriptive analyses comparing sociodemographic characteristics, drug consumption behaviors, high-risk injection behaviors, and health outcomes associated with drug use between the pre- and post-intervention periods for the whole sample as well as for only participants who used heroin. We also compared post-intervention survey responses between respondents who did and did not use a heroin pipe and by self-reported impact of heroin pipes on injection frequency.Since the majority of participants only completed one survey, we collapsed survey timepoints into two time periods  for comparisons. Furthermore, since only a small number of participants 14%) completed a survey in both the pre- and post-intervention periods, few of whom used heroin, all responses were treated as independent observations when comparing the pre- and post-intervention periods . Informed consent was obtained from all participants before beginning their first survey. Participants were compensated $5 USD after each completed survey.A total of 694 unique respondents completed 957 surveys across the seven observation timepoints. The majority  of respondents used heroin in the past seven days during one or more survey timepoint. The median age of respondents who used heroin was 35 years (IQR 29–43). The majority identified as men 61%), white (63%), and currently unhoused (54%). Nearly half (46%) reported having no monthly income. Among respondents who used heroin, 90% reported lifetime injection drug use, including 79% and 25% who had consumed drugs through IV and IM injection in the past seven days during one or more timepoint, respectively, and 83% had smoked heroin in the past seven days during one or more timepoint. Sociodemographic characteristics and drug consumption behaviors of all respondents and respondents who used heroin are summarized in Table %, white Of the 408 respondents who used heroin at any survey timepoint, 207 completed one or more pre-intervention survey, and 257 completed one or more post-intervention survey. Among respondents who used heroin, 79% (323/408) only completed one survey, and 21% (85/408) completed more than one survey, including 14% (56/408) who completed at least one survey during both the pre-intervention and post-intervention periods  and 57% (542/957) were completed during the three pre-intervention timepoints and four post-intervention timepoints, respectively. Multiple responses from a single respondent in a given period were collapsed, resulting in 790 records, of which 46% (360/790) were from the pre-intervention period and 54% (430/790) were from the post-intervention period. Heroin use was reported in the majority of pre-intervention  and post-intervention records . Measured sociodemographic characteristics did not differ significantly between the pre- and post-intervention periods , while the proportion of respondents who reported both injecting and smoking heroin was significantly higher during the post-intervention than pre-intervention period . The proportion of respondents who exclusively smoked heroin (p = 0.66), as well as median number of weekly IV injections (p = 0.15) and weekly IM injections (p = 0.16), did not change significantly comparing the periods before and after heroin pipes were distributed. Drug consumption behaviors across the pre- and post-intervention periods are presented in Table The proportion of respondents who reported exclusively injecting heroin was significantly lower during the post-intervention than pre-intervention period . The proportion of respondents who used heroin and shared syringes was lower during the post-intervention period than the pre-intervention period ; however, this difference in proportions was not statistically significant (p = 0.26). All other high-risk injection behaviors and drug use-associated health outcomes did not differ significantly between the pre- and post-intervention periods . This smaller portion of the overall sample who reported syringe reuse after implementation of heroin pipe distribution had borderline statistical significance (p < 0.001), and higher proportions of heroin pipe users exclusively smoked heroin  and both smoked and injected heroin  in the past seven days. None of the respondents who had used a heroin pipe reported first-time injection drug use or being arrested for heroin pipe possession during the post-intervention period. Hospitalization for a pulmonary cause was not associated with using a heroin pipe  used a heroin pipe from the SSP at least once within 30 days of completing a post-intervention survey. Among those who used a heroin pipe, 83% (91/110) used that pipe to smoke heroin, and 35% (38/108) had come to the SSP and been unable to procure a heroin pipe on one or more occasion because of limited stock. Compared to respondents who used heroin and did not use a heroin pipe, lower proportions of heroin pipe users exclusively injected heroin . Fewer respondents who reported heroin pipe distribution had reduced their injection frequency exclusively smoked heroin in the post-intervention period compared to respondents who stated heroin pipe distribution had no impact on their injection frequency   and 76% (189/250) reported the heroin pipe distribution program reduced and had no impact on the frequency of their heroin injection, respectively. None reported the heroin pipe program increased their injection frequency. Among the respondents who reported that heroin pipe distribution had reduced their injection frequency, a higher proportion both injected and smoked heroin compared to respondents who stated heroin pipe distribution had no impact on their injection frequency , the small number of SSP clients exposed to the intervention may have contributed to our null results. Study designs with longer follow-up periods and larger sample sizes are necessary to evaluate for less common health outcomes, including infective endocarditis as well as incident HIV and HCV infection. Additionally, there are several high-risk drug consumption behaviors  and health outcomes associated with heroin injection and inhalation  that were not measured in this pilot study . High-riMost respondents who used heroin during the post-intervention period did not receive a heroin pipe. Many programmatic and client factors may have limited exposure to the intervention. Heroin pipes were offered on a first-come first-served basis, and clients that visited the SSP later in the day were less likely to receive a pipe due to limited stock. A third of pipe recipients reported heroin pipes had been unavailable on at least one SSP visit. Our survey did not ask respondents whether they were aware of the new heroin pipe distribution program, and the program was primarily advertised informally by word of mouth. Therefore, SSP clients may not have been exposed to the intervention because they did not know to ask for a pipe. Beyond programmatic limitations, certain SSP clients may have been more likely to accept a heroin pipe when available. Exclusively injecting heroin was nearly five times more common among those who did not receive a heroin pipe than among pipe recipients, suggesting that SSP clients habituated to heroin injection may have been more likely to refuse a pipe when offered. However, 15% of respondents who exclusively injected heroin still obtained a heroin pipe on at least one occasion, which may indicate willingness to try new consumption methods. Different chemical forms of heroin are available in the USA, including hydrochloride salt and free base forms of heroin. Compared to its free base form, heroin hydrochloride salt is much less volatile and requires higher temperatures for volatilization . Some PWWe evaluated several theoretical risks associated with provision of heroin pipes through SSPs in this pilot study and found no evidence to support these concerns. Distribution of heroin pipes through an SSP could introduce heroin smokers to injection supplies, inadvertently promoting a transition from heroin smoking to injection. No heroin pipe recipients reported first-time injection during the study. Heroin smoking is associated with pulmonary disease, including potentially life-threatening asthma and chronic obstructive pulmonary disease (COPD) exacerbations , and incOur pilot study has several limitations. The absence of randomization in our pretest–posttest design does not allow us to control for confounding of unmeasured variables and prevents us from establishing causation between the intervention and outcomes. We conducted seven separate observation timepoints to reduce threats to internal validity and minimize selection bias. However, with only three pretest observations we were unable to employ the regression-based approach commonly used in interrupted time series analysis, limiting our ability to control for possible external time-varying effects or autocorrelation which may account for changes in outcomes over time. SSP clients were recruited by convenience sampling during each observation timepoint and few respondents completed surveys in two or more time periods. While changes in outcomes may have been driven by changes in the sampled population rather than changes in drug consumption behaviors of individuals, measured sociodemographic characteristics did not differ significantly between respondents who completed surveys in the pre- and post-intervention periods. We originally intended to recruit a longitudinal cohort of SSP clients and analyze changes in drug consumption behaviors of unique SSP clients over time; however, only 14% of respondents were surveyed in both the pre- and post-intervention periods. Our experience suggests text message or email reminders and small cash incentives may not be sufficient to prevent loss-to-follow-up among PWUD, and innovative strategies are needed to improve PWUD retention in longitudinal research projects. Finally, outcomes were measured by self-report, which introduce the possibility of misclassification due to recall, information, and social desirability biases. However, unless referring to lifetime use, respondents were only asked to report on behaviors occurring within the past 30 or seven days to minimize recall bias, and surveys were administered by longtime SSP volunteer staff to make respondents feel as comfortable as possible when disclosing sensitive information about their drug use and health behaviors.Our pilot study suggests heroin pipe distribution at an SSP may be a novel RTI to change drug consumption behaviors and reduce harms associated with heroin injection. Future research is needed to expand on our findings, including larger randomized trials to evaluate whether changes in drug consumption behavior prompted by pipe distribution improve downstream health outcomes. Qualitative and mixed-methods investigations would be helpful to assess acceptability and optimize delivery of heroin pipe distribution across different settings as well as evaluate the impact of this intervention on the frequency and quantity of opioids used. Access to heroin pipes may delay initiation of heroin injection by providing PWUH with an effective alternative to heroin injection. Studies outside of SSPs, where most PWUH have already begun injecting heroin, could assess whether heroin pipe distribution delays or prevents injection among people who recently started using heroin. People who inject methamphetamine and cocaine are also at risk for many of the same poor health outcomes as PWUH, and future investigations could be expanded to include methamphetamine and crack cocaine pipe distribution. Intranasal and rectal heroin administration are alternative routes of consumption which may have fewer risks compared to injection and inhalation. Other novel RTIs, including provision of supplies for heroin snorting or booty bumping, deserve further attention. Additionally, this study was conducted prior to the COVID-19 pandemic. Pipe distribution programs may prevent pipe sharing, and thereby COVID-19 transmission, among PWUD. The impact of safer smoking programs on COVID-19 outcomes should be incorporated into future research.Future research should pay particular attention to the potential impact of pipe distribution on fentanyl use. Both fentanyl injection and inhalation have become increasingly central to opioid use patterns and overdose risk in the USA . Trends Finally, this project represents the culmination of a new harm reduction service conceived, designed, and implemented by members of the drug using community. The PWUD leaders who guided this project through development deserve credit for this innovation. Peer participation and leadership is increasingly recognized as essential to finding creative solutions that effectively and ethically meet the needs of PWUD. Space should be made for PWUD leadership in future evaluations of heroin pipe distribution and other harm reduction programming.Additional file 1: Post-intervention survey.Additional file 2: Pre-intervention survey.Additional file 3: Educational materials distributed to SSP clients describing how the pipe could be used to smoke heroin.Additional file 4: Supplementary tables.


Antibiotic stewardship in urologic reconstruction is critically important, as many patients will require indwelling catheters for days to weeks following surgery and thus are at risk of both developing catheter-associated urinary tract infections (CAUTI) as well as multi-drug resistant (MDR) uropathogens. Accordingly, limiting antibiotic use, when safe, should help reduce antibiotic resistance and the prevalence of MDR organisms. However, there is significant heterogeneity in how antibiotics are prescribed to patients who need indwelling urethral catheters post-operatively. We performed a literature review to determine if there are benefits in the use of antibiotics for various clinical scenarios that require post-operative indwelling catheters for greater than 24 h. In general, for patients undergoing prostatectomy, transurethral resection of the prostate, and/or urethroplasty, antibiotic administration may be limited without increased risk of CAUTI. However, more work is needed to identify optimal antibiotic regimens for these and alternative urologic procedures, whether certain sub-populations benefit from longer courses of antibiotics, and effective non-antibiotic or non-systemic therapies. Antibiotic stewardship is a challenging but important consideration in public health and in the care of individual patient. Urologists are routinely tasked with decisions regarding antibiotic selection and duration for both acute infection as well as prophylaxis. Though routinely delivered with the intent of net benefit, there is a great deal of heterogeneity in the paradigms surrounding the use of antibiotic prophylaxis across providers, institutions, and regions at large ,2,3,4.Unique and particularly relevant to the urologist are antibiotic practices surrounding indwelling catheterization via any drainage tube that is inserted into the urinary bladder through the urethra or suprapubic region and connected to a closed collection system. There are multiple indications for the use of indwelling catheters, including management of urinary retention, careful monitoring of urine output in critically ill patients, urinary decompression, and support for healing following lower urinary tract procedures. Depending on the indication, indwelling urethral catheters may remain in situ post-operatively for days to weeks at a time. nidi for urinary tract infection (UTI). Nevertheless, there is considerable variability in the administration of prophylactic antibiotics to patients with indwelling urethral catheters following urological procedures [Indwelling urethral catheters, though necessary in many post-operative settings, are long recognized as ocedures ,2,3. Speocedures . The rationale for the use of prophylactic antibiotics in the setting of catheterization after lower urinary tract reconstruction is to decrease the likelihood of symptomatic infection and/or to reduce the likelihood of bacteriuria and associated debris, which may result in catheter obstruction. Catheter-associated urinary tract infections (CAUTI) contribute significantly to healthcare costs at an estimated $115 million to $1.82 billion annually [not prescribing antibiotics, thus reducing the development of multi-drug resistant (MDR) organisms.There remain no urologic guidelines that recommend routine utilization of prophylactic antibiotics during a period of prolonged catheterization. Continuous prophylactic antibiotics are not explicitly recommended in the setting of prolonged catheterization due to a lack of evidence that true infections are prevented ,7,8. AccComprehensive Cochrane reviews from 2012 and 2013 on antibiotic prophylaxis for short-term bladder drainage in adults  and on cEscherichia coli, Enterococcus spp., and Candida spp. [Urethral catheters are indwelling foreign bodies associated with the colonization of microorganisms (bacteria and fungus), which is temporal in nature . While mida spp. ,16.Proteus mirabilis, can aggregate and occlude the lumen of a catheter [Catheters are also vulnerable to the development of biofilm, which are matrix-enclosed microbial accretions that adhere to biological or non-biological surfaces ,18. One Approximately 75–90% of patients with catheter-associated bacteriuria (CAB) will not develop an inflammatory response or other signs or symptoms to suggest infection ,20. AlthBy definition, antimicrobial prophylaxis is preventive in nature: it may be considered primary prevention  or secondary prevention (prevention of the recurrence or reactivation of an infection) . AntibioThis is most likely related to a relative lack of evidence and relevance as compared to indwelling catheters in other settings . The AUA recommends antibiotic prophylaxis at the time of postoperative catheter removal in certain settings , whereasAs outlined previously, the available societal guidelines from the AUA, EAU, IDSA, and CDC do not explicitly recommend the routine use of continuous prophylactic antibiotics to prevent CAB or CAUTI in patients with indwelling urethral catheters. Across these groups, there are conflicting recommendations for or against antibiotic prophylaxis at the time of catheter removal or exchange based largely on patient factors. With this review, we aim to explore if there are clinical scenarios in which the use of antibiotics in patients with temporary indwelling urinary catheters remaining longer than 24 h is of benefit following urologic procedures. We then summarize the findings for each clinical scenario and highlight our recommendations (in bolded text). We adhered to standards as outlined by Baethge et al. to optimize review quality and relevance .We evaluated studies centered on antibiotic prophylaxis for post-operative catheterization in patients who underwent urologic procedures with an anticipated duration of catheterization > 24 h. We included randomized controlled trials, prospective descriptive studies, retrospective quasi-experimental studies, and surveys.We included studies with adults (age ≥ 18 years) requiring post-operative indwelling urethral catheterization  following urologic procedures, including radical prostatectomy, transurethral resection of the prostate, holmium laser enucleation of the prostate (HoLEP), transurethral resection of bladder tumor, bladder diverticulectomy, partial cystectomy, urethral diverticulectomy, and urethroplasty.Interventions considered were continuous antibiotic prophylaxis for the duration of catheterization, antibiotic prophylaxis at the time of catheter removal only, and no antibiotic prophylaxis. We performed an electronic search to identify relevant studies from PubMed. We limited our search to full-text articles that were available in the English language. No automation screening tools were used.The search terms utilized were:(antibiotic prophylaxis)AND(urinary catheter)AND(prostatectomy) or (RALP) or  or (TURP) or (holmium laser enucleation of the prostate) or (HoLEP) or  or (TURBT) or (bladder diverticulectomy) or  or  or (urethroplasty).Authors FM and CC independently assessed all titles and abstracts identified by the search for relevance to the topic. Where there was any possibility that the study might be included, the full paper was obtained and reviewed. Where discordance existed, a consensus was reached by FM, CC, and JC. The date of the most recent search of the register for this review was 11/25/2022. Outcomes of interest included symptomatic lower urinary tract infection/cystitis, fever, sepsis, catheter malfunction, and cultures with MDR bacteria. The presence of these outcomes was based on their study-specific definitions rather than pre-existing criteria set by the authors of this review.In our PubMed search, we did not find relevant articles concerning antibiotic prophylaxis for indwelling urethral catheterization following holmium laser enucleation of the prostate (HoLEP), transurethral resection of bladder tumor, bladder diverticulectomy, partial cystectomy, or urethral diverticulectomy. Patients undergoing radical prostatectomy require temporary use of an indwelling urinary catheter after surgery for primary healing of the vesicourethral anastomosis. Typically, the catheter remains in place for six to fourteen days, depending on the surgeon’s preference.A 2013 study prospectively examined urine cultures obtained from patients who underwent radical prostatectomy immediately prior to catheter removal on postoperative day (POD) 10. All patients received prophylactic antibiotics surrounding catheter removal with oral ciprofloxacin beginning the night before catheter removal and continuing afterward for a total of seven days. Of 334 patients, 83 (25%) had positive cultures with organisms > 1000 CFU/mL, of which 7% were resistant to ciprofloxacin. The authors concluded that a substantial proportion of prostatectomy patients have positive urine cultures at the time of catheter removal despite the administration of prophylactic fluoroquinolone antibiotics. However, outcomes were favorable overall when culture-specific oral antibiotic therapy was initiated. Nevertheless, the benefits of antibiotic administration in the setting of this study were difficult to assess without a control arm [Shin and colleagues compared infectious outcomes after radical prostatectomy between two different antibiotic protocols. Specifically, 153 patients were administered a cephalosporin for fewer than 2 days, and 160 patients received a cephalosporin for more than 2 days. The presence of bacteriuria was examined at the time of catheter removal on POD 14. The researchers reported that the overall incidence of bacteriuria was 51% post-operatively and significantly higher in patients receiving the shorter antibiotic protocol compared to the longer protocol (57% vs. 45%). However, the incidence of fever was not significantly different between the two groups .Pinochet and colleagues retrospectively examined rates of symptomatic UTI in patients who underwent radical prostatectomy by one of two surgeons. One surgeon routinely prescribed a 3-day course of ciprofloxacin prophylaxis starting the day before catheter removal on POD 11; the other surgeon prescribed no antibiotics prior to catheter removal, which was performed on POD 7. Despite a longer catheterization, the group of patients who received antibiotics was observed to develop fewer UTIs in their post-operative course (3.1 vs. 7.3%). Fever was observed in 11 patients in the non-antibiotic group (2.4%); there were no fevers in patients receiving antibiotic prophylaxis. Based on their statistical analysis, the number needed to treat to prevent one UTI was estimated at 24, and to prevent one case of febrile UTI was 91 . While these studies suggest there may be an advantage to the routine use of antibiotic regimens of longer duration, other studies have not. A 2017 study examined rates of CAUTI following a change of practice at their institution from a protocol of a prolonged course of prophylactic antibiotics following radical prostatectomy  to perioperative prophylaxis only. No significant difference in the incidence of CAUTI was noted .Several studies have also examined administering antibiotics at the time of catheter removal only. In 2019, Berrondo and associates performed a prospective randomized controlled trial to evaluate the role of antibiotic prophylaxis prior to urinary catheter removal after radical prostatectomy in preventing UTI. The 167 patients were randomized to receive antibiotic prophylaxis  or to receive no antibiotics. Overall, eight (4.8%) patients developed symptomatic UTIs within 6 weeks of urinary catheter removal. No significant difference in the rate of UTI between the control group and the antibiotic prophylaxis group (5.95% vs. 6.02%) was observed . AnotherWhen taken together, these studies suggest that among patients after radical prostatectomy, a peri-operative dose of antibiotics only or a peri-operative dose of antibiotics plus a one-day course around catheter removal for patients may provide adequate prophylaxis against UTI while reducing the duration of antibiotics prescribed.Although patients undergoing radical prostatectomy undergo lower urinary tract reconstruction, catheter duration is typically less than 1 week, all patients have male anatomy, and patients are considerably less likely to enter surgery with indwelling hardware or recurrent infections than many other patients undergoing lower urinary tract reconstruction for other indications. Therefore, it is not known if these conclusions can be extrapolated to patients undergoing procedures such as bladder diverticulectomy, partial cystectomy, or fistula repair.Transurethral Resection of the Prostate (TURP) is an endoscopic procedure commonly performed to help relieve bladder outlet obstruction. In general, the literature centers on a comparison of perioperative prophylactic antibiotics versus no perioperative prophylaxis rather than antibiotic prophylaxis, throughout the duration of post-operative indwelling catheterization. In 1994, Raz and associates randomized 101 patients undergoing TURP to either receive a prophylactic antibiotic regimen consisting of a single dose of ceftriaxone at the time of surgery and another dose at the time of catheter removal (3 to 4 days post-operatively) or no prophylactic antibiotics. Over the entire 28-day study period, bacteriuria appeared in six ceftriaxone-treated patients and in 20 control patients. Three ceftriaxone-treated patients developed symptoms of UTI requiring additional antibiotics versus 14 control patients. Moreover, the incidence and duration of fever were shorter in the patients treated with ceftriaxone, supporting the routine use of periprocedural and peri-catheter removal antibiotics .A 1996 RCT by Hall and colleagues evaluated the prevention of UTI after TURP following various lengths of prophylaxis with a quinolone antibiotic (fleroxacin). The authors compared the efficacy of (1) a single perioperative oral dose, (2) a single perioperative intravenous (IV) dose, and (3) an initial perioperative IV dose followed by a daily oral dose until removal of the urinary catheter for up to 6 days. Only one patient developed a UTI (single dose IV group), which occurred 22 days postoperatively. There were no instances of urosepsis, nor was there a significant difference in rates of fever between groups. The researchers concluded that a single oral dose of a fluoroquinolone agent is adequate prophylaxis for patients undergoing TURP . More reInterestingly, a study by Conn and colleagues found no benefit from the use of any prophylactic antibiotics at the time of TURP. The 200 patients were randomized to receive a prophylactic antibiotic regimen consisting of a single dose of cephradine at the time of surgery and another dose at the time of catheter removal (3 to 4 days post-operatively), or to receive no prophylactic antibiotics at all. Between the two groups, there was no significant difference in rates of fever or UTI . The authors concluded that the short-term antibiotic regimen was not of benefit to patients in this setting .Overall, investigations into the use of antibiotics in patients with indwelling catheters after TURP tend to support minimizing antibiotic use in patients without preoperative infection to a single perioperative dose and possibly a single prophylactic dose at the time of catheter removal.These findings are likely to be applicable to other endoscopic outlet reduction procedures, such as water jet ablation, photo vaporization, and laser enucleation. However, with improved hemostasis, catheter duration and manipulation may be minimized, potentially limiting infectious risk.Given the typically longer indwelling catheter time utilized after urethroplasty, the practice patterns of reconstructive urologists in postoperative antibiotic utilization range widely. McDonald and colleagues administered a survey regarding antimicrobial practice patterns to 34 international members of the Society of Genitourinary Reconstructive Surgeons (GURS) who commonly perform urethroplasty. 18 to 24% of respondents continue intravenous antimicrobials for longer than 24 h post-operatively. 61% administer oral antimicrobials until postoperative catheter removal, which can occur anywhere between 2 and 4 weeks), and the majority give additional antimicrobials at catheter removal [p = 0.36) or wound complications (p = 0.42) between patients who had a positive and negative urine culture. On adjusted analysis, positive urine cultures  were not associated with stricture recurrence. The rates of catheter malfunction were not reported [Manjunath et al. retrospectively examined close to 400 patients who underwent urethroplasty by a single surgeon from 2000 to 2012. All patients received preoperative antibiotic prophylaxis and postoperative prophylaxis for 30 days or until catheter removal. The investigators identified 102 (25.6%) positive urine cultures (defined as >1000 cfu/mL of an organism) within 30 days of urethroplasty—cultures were collected if there was a concern for UTI . There were no significant differences in stricture recurrence (reported .n = 60) received extended postoperative antibiotics for 3 weeks until catheter removal, and patients in group 2 (n = 60) received antibiotics for 3 days around catheter removal. They defined a UTI as a positive urine culture or reported lower urinary tract symptoms/fevers treated with empiric antibiotics. There was no significant difference in UTI  or wound infection rates  between the two groups [p = 0.064) and 3.9% , respectively. Given these findings and concerns about the overprescribing of antibiotics, they did not recommend prolonged antibiotic use after urethroplasty [Several studies have assessed the impact of antibiotic duration. Baas and colleagues performed a retrospective review of patients who underwent urethroplasty from September 2017 to March 2020 by a single surgeon, where patients in group 1  and completely absent for others . Furthermore, no subpopulations have been identified as a group that would benefit from additional antibiotic prophylaxis. However, this is more a story of “absence of evidence” rather than “evidence of absence.”not be administered with indwelling catheters. The IDSA, whose experts may be most acutely aware of the dangers of the rising prevalence of MDR pathogens, recommend antibiotics to prevent infection associated with the presence, placement, or removal of catheters [Societal guidelines are helpful but ultimately only as good as the data on which they are based, which is, unfortunately, limited. The AUA Best Practice Statement  and EAU atheters ,47. It would be reasonable to extrapolate societal recommendations to urologic reconstruction and recommend against continuous antibiotic administration with indwelling catheters and against any or at least routine use of antibiotics at the time of catheter removal. However, a close review of references on which societal recommendations are based finds that they may come from meta-analyses encompassing a fairly heterogeneous group of non-urologic procedures and even non-urinary drains ,11. ThisImportantly, the outcomes of existing studies center around the presence of bacteriuria or the development of symptomatic infection and do not address more surgically relevant outcomes of catheter malfunction and associated morbidity. Prevention of bacteriuria is likely not possible ,15,19,20What is also apparent is the need for non-antibiotic strategies to prevent postoperative CAUTIs and catheter malfunction. In the setting of chronic and short-term catheterization, these strategies have included antibiotic and non-antibiotic bladder irrigations ,49,50, nLimitations of our manuscript are those inherent to literature reviews, including potential author bias and failure to identify and therefore include studies relevant to the topic. We aimed to mitigate these risks with multi-author identification and review of studies for inclusion and broad search criteria. In addition, this review is limited by the relative quality of the literature, requiring liberal inclusion criteria . Nevertheless, we believe this review has value in highlighting both important findings that inform clinical decision-making and areas where deficient study warrants future research.Antibiotic stewardship demands limiting the use of antibiotics in patients undergoing urologic procedures who require indwelling catheterization for >24 h. Limited data in patients following TURP, radical prostatectomy, and urethroplasty suggests that, in general, avoidance of continuous prophylaxis does not result in a greater risk of symptomatic infection. A single dose of antibiotics at the time of catheter removal may be warranted in some patients to prevent infection. However, this population has yet to be defined. Opportunities for improvement in future study design include additional outcome variables that improve our understanding of the impact of catheter malfunction on outcomes and the impact of antibiotics on catheter malfunction. Given the concerning rise in the prevalence of MDR pathogens and the association of MDR organisms with systemic antibiotic administration, the development of non-antibiotic strategies is paramount.


In the case of concrete sustainability, two main ways are generally discussed: (1) the reduction of natural raw materials and (2) the reduction of emissions related to concrete production. Following the second point, there have not yet been reported clear results. This problem is not given enough attention in present publications. This study brings a general view of this issue and a basic comparison with common concrete and traditional reinforcement. This case study deals with the life cycle analysis of a concrete slab made of recycled aggregate concrete with a fine recycled aggregate. The concrete slab was designed according to the limit states of load-bearing capacity and serviceability, which is based on the experimental verification of recycled aggregate concrete properties. Two different reinforcements are compared: (1) ordinary reinforcement by steel bars and (2) glass fibers. Furthermore, scenarios vary due to the slab thickness and reinforcement percentage. The results show the positive environmental impact of replacing natural sand with a fine recycled aggregate. The reduction of climate change potential can be almost 40% in some cases. For this reason, one of the main possibilities to reduce the negative environmental impact of the building sector is to find a more sustainable solution in concrete production. It could be said that the clear way is to replace the natural aggregate (NA), which is approximately 70% of the largest component of concrete, with a recycled one (RA) . Howevern ~15%) ,4,5,6,7.% ,4,5,6,n (~15%) . Furthern (~15%) .2 emissions by only up to 2% [The majority of the published studies dealing with the life cycle assessment (LCA) of RAC investigate the impact of coarse fraction replacement ,14,15,16up to 2% . Moreoveup to 2% ,19. Furtup to 2% . Furtherup to 2% .On the other hand, it is necessary to know that the sand supplies are not infinite and the extraction of sand induces much environmental damage worldwide, including the erosion and damage of landscapes.Furthermore, the LCA is strongly affected by the functional unit (FU), system boundaries, allocation, LCI, and others. Historically, only the RA and NA have been compared , and theThe main aim of this study is to analyze the environmental impact of concrete slabs made of RAC where the natural sand (fNA) is fully replaced by the fRA (fine recycled masonry aggregate fRMA and fine recycled concrete aggregate fRCA). The design of the slab was based on the limit states of load-bearing capacity (LBC) and serviceability (SA). The design of the structural elements is established according to the experimentally verified properties of concrete. The LCA method of evaluation of the environmental impact was used for this case study. The novelty of this study is a comprehensive approach to the LCA case study of the concrete structural elements with the full replacement of sand in the mixture, various concrete mixtures, reinforcement types, and design approach.In total, six concrete mixtures were experimentally verified for the possible replacement of natural sand by an fRA. The concrete mixtures contained two types of fRA (fraction 0–4 mm), coarse NA (fraction 4–16 mm) see , two amoThe two types of fRA were used as a replacement for natural sand in the concrete mixture. The fRCA is produced by crushing waste concrete from CDW ,35,36,373 ordinary Portland cement (OPC) CEM I 42.5 R and the predicted effective water–cement ratio was 0.65, and mixture II contained 300 kg/m3 cement CEM I 42.5 R and the predicted effective water–cement ratio was 0.55. The target effective water–cement ratio was determined from the water absorption of the fRA and predicted effectiveness of sorption capacity during mixing. The Bolomey particle size distribution curve was used for optimizing the skeleton of the concrete mixtures. The two-stage mixing approach [The six concrete mixtures were produced for experimental examination of the mechanical properties and durability. Mixture I contained 260 kg/m3, and the modulus of elasticity and flexural strength were tested on beams 100 × 100 × 400 mm3, all at age 28 days by Controls MCC8 50-C8422/M  according to the relevant standards . The carbonation resistance (ČSN EN 12390-12) was tested on beam samples 100 × 100 × 400 mm3 at age 28 days by CO2CELL (MMM group) and freeze–thaw resistance was tested according to ČSN 73 1322 on beam samples 100 × 100 × 400 mm3 at age 28 days for 100 freezing–thawing cycles by KD20 .The physical and mechanical properties and frost and carbonation resistance, the properties relevant to the structural utilization, were experimentally verified. The results of the evaluation were used for the structural design. The compressive strength was tested on cubes 150 × 150 × 150 mmIn previous studies, it has been presented that the compressive strength is significantly influenced by the fRA until 30% of the substitution level; however, in the case of modulus of elasticity, the decline can be observed already at lower replacement ratios . For thiTo analyze the potential environmental impacts of product systems, the LCA method was used. According to ISO 14040:2006 , LCA wasThe goal of this study was to compare six concrete mixtures used in concrete slabs containing glass or steel reinforcements, which were designed to fulfill requirements for the limit states of load-bearing capacity and serviceability. In this study, the function of compared concrete slabs differ based on their limit states. Therefore, designs related to the limit states of load-bearing capacity and serviceability are compared separately.The product systems were compared in the scope of system boundaries, which can be described as cradle-to-grave. Thus, system boundaries cover the production of raw materials (including recycling processes for the production of recycled aggregates) and their transport, preparation of the concrete mixture, production of the concrete slab, deconstruction, and its assumed end of life (EoL), which consists of deconstruction, transport for disposal, and landfilling as the most common process for the disposal of concrete in the Czech Republic.The referential flows of concrete mixtures for each slab are summarized in The GaBi 9 software was used to conduct the data and model the product system. The production of recycled aggregates was modeled based on specific data from the producer and other processes were modeled using generic data from the GaBi 9 database . For theThe potential environmental impacts related to the considered product systems were calculated according to the environmental footprint (EF), version 3.0 characterization method. Using normalization and weighting of these results, the overall impact of each concrete slab was calculated. Normalized results were estimated by relating the results of the environmental indicators to the global impact using the factors according to EF 3.0 personal equivalents provided in the GaBi software v2022.2. To consider the specific value of each impact category, the weighing factors according to EF 3.0 were applied using the GaBi software. The results of the calculations provide basic data on material consumption for the next step to evaluate the LCA and make an overall evaluation. The design and calculation of the limit states of load-bearing capacity and serviceability were performed according to the Eurocode 2, specifically the ČSN EN 1992-1 standard. A typical ceiling panel with a span of 6 m was chosen to calculate and compare the variants. The panel is solid without cavities and lightening, and a common meter of panel width is considered. ykf 500 MPa, and the modulus of elasticity sE 200 GPa. For the AR-glass FRP reinforcement data from the technical data sheet reference, the real tensile strength yk,realf 1050 MPa and the real modulus of elasticity s,realE 50 GPa were used.The input parameter for the calculations was the experimentally determined compressive strength of concrete for different formulas. Furthermore, the static modulus of elasticity of concrete was entered into the calculation, which was also determined experimentally. The E modulus was included for the serviceability limit state. The input parameters for the reinforcement were the mechanical parameters for traditional steel reinforcement, the tensile strength q category A was considered, which means 1.50 kN/m2, and also moveable partitions 1.2 kN/m2. Additionally, floor self-weight g1 was a constant 2.05 kN/m2 calculated from the self-weight of the typical selected floor composition. The self-weight of the reinforced concrete panel g2 was calculated based on its designed thickness. The sum of these loads is the continuous load of the panel. With the considered width of 1.0 m and the simply supported panel, it is then easy to calculate the bending moment.The constant floor live load c of the reinforcement was considered as a constant regarding the durability of traditional steel reinforcement. A thickness of 20 mm for reference concrete from a natural aggregate and 35 mm for concrete with a recycled aggregate of concrete cover was considered, based on the results of carbonation resistance according to the ČSN EN 12390-12 standard. For the AR-glass FRP reinforcement, there is no need to propose the reinforcement concrete cover regarding durability, but only regarding the aggregate size and interaction conditions of the reinforcement and concrete, allowing full reinforcement activation. A constant value of 15 mm was selected as the concrete cover of AR-glass FRP reinforcement.Steel reinforcement, thickness modification’, for the limit state of load-bearing capacity includes traditional steel reinforcement and adjustment of the concrete thickness to comply with the conditions of the load-bearing capacity for different concrete mixtures and other sub-conditions of the calculation. The amount of reinforcement in the cross-sectional area was constant for this case; the reinforcement diameter was considered as 10 mm with an axial distance of 100 mm. The thickness of the panel was changed according to the measured strength of the concrete mixture.The calculations for the first group in GFRP reinforcement, thickness modification’, for the limit state of load-bearing capacity includes AR-glass FRP reinforcement and adjustment of the concrete thickness. The amount of reinforcement in the cross-sectional area was also constant for this case; the reinforcement diameter was considered as 6 mm thanks to its better tensile strength with an axial distance of 75 mm. The effect of the lower concrete cover was also positive. The thickness of the panel was very slightly changed to achieve the necessary load-bearing capacity. It was also possible to notice a change in the thickness of the panel. This is due to the condition of restricting the position of the neutral axis of the panel in bending.The next group in Steel reinforcement, reinforcement modification’ in The group ‘GFRP reinforcement, reinforcement modification’ in The group ‘Next, c of the reinforcement was considered, as in the previous case of the design for the limit state of load-bearing capacity. Then, the thickness of the panel or the reinforcement area was modified for different concrete classes with experimentally determined parameters and steel and AR-glass FRP reinforcement. Results were used in the next step to evaluate LCA.The basic thickness of the concrete panel was optimized for NAC according to the conditions of serviceability with a limited deflection in the middle of the span of the panel at 24 mm. In addition, conditions of the limit state of load-bearing capacity were of course satisfied, with an ordinary amount of reinforcement in the first step for NAC and steel reinforcement. It means that an ordinary diameter and spacing of reinforcements for the considered panel spanning concrete cover Steel reinforcement, thickness modification’ in The first group of calculations labeled ‘GFRP reinforcement, thickness modification’ of The next group ‘Steel reinforcement, reinforcement. Modification’ in The group labeled ‘GFRP reinforcement, reinforcement modification’ in The group labeled ‘2 of a solid concrete slab had a thickness of 0.25 m with a constant reinforcement ratio. On the contrary, in this LCA case study, the environmental impact of the reinforcement concrete slab, where the decline of the properties is compensated by the additional slab height or reinforcement level, is analyzed. Although the decline of properties, especially the modulus of elasticity, caused an increase in the slab height or reinforcement level, the normalized and weighted results for concrete show the positive environmental impact of replacement fNA by an fRA  can be observed. The maximal increase was 23 kg CO2 eq which corresponds to 5%.In the case of the climate change indicator describing the effect on global warming see , the resGenerally, from the reinforcement type point of view, the results of the climate change indicator differ for limit states. In the case of the LBC limit state, a more sustainable option seems to be glass fiber reinforcement; on the contrary, in the case of the SA limit state, steel reinforcement can be observed as the more favorable solution. It is possible to observe similar trends for all assessed types of concrete slabs. For this reason, the type of reinforcement is not straightly correlated with the concrete type.In the case of compensating the properties of an fRAC by the (1) varying thickness of the slab and (2) varying reinforcement level, the results are similar to normalized and weighted results. For all assessed mixtures, the reduction of the climate change impact is more significant when the decline of properties is compensated by more reinforcement.3 of OPC and (II) with 300 kg/m3 of OPC. In the comparison, in the perspective of the design oriented to the load-bearing limit state, the result of the climate change indicator is slightly higher for concretes containing more cement where the design of the concrete slab is based on the LBC limit state, and so compressive strength. On the contrary, in the SA limit state point of view, the GWP differs significantly, and it is more favorable for mixtures with higher amounts of cement and, consequently, better mechanical properties, especially the modulus of elasticity.In addition, concrete mixtures with two amounts of cement were assessed. Concrete (I) contained 260 kg/mConsidering the results of the climate change indicator, similar conclusions can be drawn based on the results of other environmental indicators, which are presented in the The result of the potential impact in the ozone depletion category is influenced by the use of glass reinforcement production see a,b, therThe results of the ecotoxicity potential indicator are in accordance with results of the climate change indicator see c,d. The In the case of eutrophication potential e,f, the The impact in water depletion potential mainly comes from cement production and landfilling, but an even higher impact is caused by epoxy resin production, which contributes more than the total impacts related to cement production and landfilling. Despite the burden of epoxy resin production, in the comparison of materials for roving, glass and steel reinforcement reach approximately the same result of WDP. Based on results presented in In this study, the environmental impact of concrete slabs made of recycled aggregate concrete where the natural sand is fully replaced by the fine recycled masonry aggregate and fine recycled concrete aggregate was analyzed. The design of the structural elements was established according to the experimentally verified properties of concrete. The design of the slab was developed aiming at two limit states (load-bearing and serviceability) and considering the use of two different reinforcement materials (steel and glass). Moreover, two approaches to compensate for the decrease in recycled aggregate properties were used to design 48 scenarios.Generally, the results show a strong positive influence on the environmental impacts for the mixtures containing a fine recycled concrete aggregate. The decrease in the result of the climate change indicator was essential. However, the replacement of natural sand by fine recycled concrete aggregate has either no impact, or an insignificant impact, on the mechanical properties of concrete, which is the probable reason for very positive results in the LCA analysis.In the case of compensation for the decline of mechanical properties, the results show a lower environmental impact for a higher reinforcement level in comparison with increasing the slab thickness.The design of the slab was based on the limit states of load-bearing capacity (LBC) and serviceability (SA), where the LBC is based on the compressive strength and SA on the modulus of elasticity. The results of the LCA case study show the differences between these two approaches. Generally, the concrete slab was significantly larger in the SA design approach. In addition, the results of the environmental assessment differ in the case of reinforcement type, where the results for these two design approaches were exactly the opposite. The use of steel reinforcement is more advantageous for the SA limit state and, on the contrary, the glass fibers are better in the LBC approach, which is caused by the increase of slab thickness due to the minimal reinforcement level.The results of the climate change indicator show similar or slightly higher values for mixtures containing a fine recycled masonry aggregate than reference mixtures with natural sand. On the contrary, the normalized and weighted results show a slightly positive impact of replacing the natural sand, which shows a positive effect in the other impact categories.Based on the results of the environmental assessment of these scenarios using the LCA method, the following conclusions can be drawn:This study presented a comprehensive approach to the LCA case study of the concrete structural elements with the full replacement of sand in the mixture. The results showed a clear positive environmental impact, especially for the fine recycled concrete aggregate, where the decline of mechanical properties was insignificant and so the environmental benefits are essential. According to the reported results, the use of a fine recycled aggregate as a substitution for natural sand in the concrete mixture has clear environmental benefits, which not only prevent the erosion and destruction of the landscape, but also lead to reduced global impacts such as climate change.


A comprehensive small area description of regional variations in outpatient antibiotic prescribing in Germany is lacking. Using the German Pharmacoepidemiological Research Database (GePaRD), a claims database covering ~20% of the German population, we determined the age- and sex-standardized prescription rates of antibiotics (number of outpatient prescriptions per 1000 persons/year). We calculated these prescription rates overall and on the level of 401 German districts for the calendar years 2010 and 2018. In 2018, the standardized prescription rate of antibiotics in the total study population was 23% lower than in 2010 (442 vs. 575 per 1000 persons/year). Among 0–17-year-olds, prescription rates across districts ranged from 312 to 1205 in 2010 and from 188 to 710 in 2018 per 1000 persons/year; among adults (≥18 years), they ranged from 388 to 841 in 2010 and from 300 to 693 in 2018 per 1000 persons/year. Despite the overall decline in outpatient antibiotic prescribing between 2010 and 2018, regional variations at the district level remained high in all age groups in Germany. Identifying reasons that explain the persistently high prescription rates in certain regions will be helpful in designing effective and tailored measures to further improve antibiotic stewardship in these regions. Antibiotics are important for the treatment of bacterial infections, and antibiotic resistance is one of the main challenges for health systems worldwide. Previous antibiotic exposure is a key driver of antibiotic resistance in humans . TherefoCompared to other European countries, Germany belongs among those with the lowest amount of outpatient antibiotics prescribed: in 2019, Germany ranked fifth among 30 countries reporting respective data to the European Surveillance System . In addiHowever, a small area (district-level) description of regional variations in outpatient antibiotic prescribing in Germany, i.e., beyond the federal states, is entirely lacking for adults and only available for the year 2010 for children and adolescents . Such a In this paper, we present the study design and results of the first part of the SARA project, i.e., a description of the current status and changes in outpatient antibiotic prescribing in Germany in 2018 compared to 2010, with a special focus on regional variations in antibiotic prescribing on the level of 401 German districts (stratified by age groups).GePaRD is based on claims data from four SHI providers in Germany and includes information on persons who have been insured with one of the four participating SHI providers since 2004 or later ,8. Per dWe conducted cross-sectional analyses for the calendar years 2010 and 2018. We selected the year 2010 to describe changes over a longer period of time and also to complement and facilitate comparisons with previous research which was restricted to children . The yeaFor each person, we assessed outpatient antibiotic prescriptions based on the ATC codes J01  and P01AB01 (“metronidazole”), using the date of prescription to assign them to calendar years. According to the classification in pharmacological subgroups (ATC 3rd level), individual antibiotic agents were grouped into subgroups .For each person and separately for both calendar years, we determined the region of residence on the district level (“Kreise und kreisfreie Städte”). Since there have been changes in the classification of districts between 2010 and 2018—mainly because some districts were merged—we standardized all districts to the status of 2018. Accordingly, our analysis includes 401 districts.We calculated the prescription rate overall for both calendar years and stratified by sex and age . For 20To describe regional variations in antibiotic prescribing at the district level and over time, we determined the prescription rate in each district for children below school age (≤6 years), for children and adolescents combined (0–17 years), and for adults (≥18 years) for both calendar years. For the calendar year 2018, we additionally calculated the prescription prevalence. We first excluded districts with fewer than 100 eligible insured persons in the corresponding age group for the graphical presentation to ensure reliable coverage. As a result, 4 of the 401 districts had to be excluded. To classify districts with lower or higher antibiotic prescribing, we then categorized the remaining districts—according to the prescription rate or the prescription prevalence, respectively—into five classes using the Jenks natural breaks classification method, which automatically identifies jumps in continuous data values and objectively maximizes the differences between classes . The natTo account for differences in the sex and age structure of the study population in the different regions and calendar years, prescription rates and prescription prevalences were directly standardized according to age/sex (as appropriate). The reference population for standardization was the German population as of 31 December 2017.In this study, the term “eastern Germany” refers to the federal states Brandenburg, Mecklenburg-Western Pomerania, Saxony, Saxony-Anhalt, and Thuringia—i.e., the states of the former German Democratic Republic (“East Germany”)—as well as Berlin in its entirety .Jenks natural breaks were calculated using R , package BAMMtools (version 2.1.7) . DescripThe entire study population comprised 13.4 and 16.7 million persons in 2010 and 2018, respectively . More thIn both years, the standardized prescription rate of antibiotics for males and females combined was highest in the age group 2–5 years (2018: 568 per 1000 persons/year) and lowest in the age group 10–14 years (2018: 236 per 1000 persons/year) . In the prevalence in the different age groups are shown and described in the Regional variations in antibiotic prescribing based on the prescription Our study on outpatient antibiotic prescribing in Germany found substantial regional variations in outpatient antibiotic prescribing at the district level in both minors and adults. In addition, the study showed a substantial decline in prescription rates: In 2018, we found an overall standardized prescription rate of 442 per 1000 persons/year, which was almost 25% lower compared to 2010. In 2018, prescription rates were above 500 per 1000 persons/year in the age groups 2–5 years and ≥65 years. However, compared to 2010, the decline was markedly higher in those aged 2–5 as compared to those ≥65 years (47% vs. 15%). Despite the overall decline in prescription rates, the relative differences in prescription rates between districts remained high in 2018—the rates differed up to almost fourfold among minors (0–17 years) and up to more than twofold among adults (≥18 years). In western Germany, prescription rates generally tended to be higher than in eastern Germany, and this difference increased in minors between 2010 and 2018. In all age groups, the highest prescription rates were found near the western border of Germany.Our results regarding the overall pattern of outpatient antibiotic prescribing—i.e., independently of the region—are similar to those from Holstiege et al. . This apWhile the overall decline in prescription rates observed in our study suggests that the measures taken in the context of antibiotic stewardship programs in Germany were effective, our findings also illustrate a need for further improvement, particularly in certain regions. In 2018, there were still marked differences in prescription rates across districts unlikely to be explained by variations in the prevalence of infectious diseases. The differences may have been due to local cultural variation ,18,19, eThere are specific strengths and limitations to be considered in the interpretation of our results. Our study is the first to provide a small area description of regional variations in outpatient antibiotic prescribing on the district level in Germany for both minors and adults. The large differences in antibiotic prescribing between districts of the same federal state demonstrate that describing regional variations solely on the federal state level is not sufficient. The detailed small area description in our study was possible due to the large claims database used. The database is free of recall and non-responder bias, and it provides a valid denominator for calculations of prevalences or rates. It also includes outpatient data from all types of providers . Another strength of our study is that—in contrast to most earlier studies—we used more than one measure to evaluate regional variations in antibiotic prescribing . Following the rationale provided by Holstiege et al. , we usedOur study also has limitations. First, given that German claims data do not contain information on antibiotics prescribed in hospitals, our study focused on outpatient antibiotic prescribing. However, as the vast majority of antibiotics are prescribed in the outpatient sector , we thinIn conclusion, our study shows that—despite the overall decline in outpatient antibiotic prescribing between 2010 and 2018—regional variations on the district level remained high in all age groups in Germany. Identifying reasons that explain the persistently high prescription rates in certain regions will be helpful in designing effective and tailored measures to further improve antibiotic stewardship in these regions.


It was found that the concrete hybridized with 0.75% KF and 0.75% GF (HF-G 0.75 K 0.75) had the most enhanced overall mechanical properties, illustrating its potential to be utilized in the rehabilitation of bridges and structures.Reinforced concrete is used in the construction of bridges, buildings, retaining walls, roads, and other engineered structures. Due to seismic activities, a lot of structures develop seismic cracks. The rehabilitation of such structures is necessary for public safety. The overall aim of this research study was to produce a high-performance hybrid fiber-reinforced concrete (HPHFRC) with enhanced properties as compared to plain high-performance concrete and high-performance fiber-reinforced concrete (HPFRC) for the rehabilitation of bridges and buildings. Kevlar fibers (KF) and glass fibers (GF) with lengths of 35 mm and 25 mm, respectively, were added and hybridized to 1.5% by mass of cement to create hybrid fiber-reinforced concrete mixes. Eight mixes were cast in total. The compressive strength ( Concrete is the most frequently used material in structures around the globe. Concrete deteriorates over time, while seismic activities can also reduce the life of a structure by damaging it. Except for a few conventional materials, other advanced materials are not yet well developed or universally implemented and their repair capabilities and long-term maintenance requirements have not been investigated . StructuIn recent years, a lot of high-strength fibers have been made available on the market, which can be used to make even more durable and long-lasting concrete for rehabilitation purposes. The concrete itself must have high performance to incorporate these fibers and in order to use their strength to the full extent. High-performance FRC and high-strength FRC are growing rapidly due to the design requirements for reducing the mass of structures and smaller sections, which ultimately has led to the cost-effective design of seismic-resistant structures. Fibers in ultra-high-performance concrete show improved properties and have been proven as excellent overlay rehabilitation materials with excellent bond strength when combined with previously damaged concrete . Each fiMany researchers have worked on the rehabilitation of structures using different materials. Normally damaged concrete components are rehabilitated by overlaying rehabilitation materials. Jacketing columns can increase the load-carrying capacity and can also help gain lost strength; the load-carrying capacity increases with increases in the jacketing area . AnotherThe research motivation is to provide an enhanced material for the rehabilitation of structures, which is emerging as a large industry around the globe, as concrete requires repair after exposure to harsh environmental effects, wear and tear, and seismic activities. If rehabilitation is not properly performed, the structure at risk may fail, which can result in many causalities. Cracks that develop in structures due to seismic activity may cause moisture to reach the reinforcement and cause corrosion . CorrosiFor the rehabilitation of concrete bridges and structures, Kevlar and glass fibers were hybridized in high-performance concrete in different percentages to evaluate their behavior and mechanical properties, keeping in mind the previous literature on hybrid fiber-reinforced concretes and rehabilitation. The mix designs and fiber percentages were chosen on the basis of the most suitable results in the trial testing. The materials were physically investigated before the mixes were prepared. ACI 211 guidelines were used to prepare the mix designs. The flow chart of this research study is shown in The ingredients were batched by weight at a mix design ratio of 1:1.2:1.8 (cement/sand/aggregate) with 8% silica fumes (SF) and 0.6% high-performance water-reducing agent by mass of cement, mixed at a W/C + SF ratio of 0.31 for the high-performance concrete named the control mix (CM). The mix design ratio was selected after trial testing. The mix proportion for the control mix is shown in Kevlar and glass fibers were used in this study. The type of Kevlar used was Kevlar 29 and type of glass used was E-Glass fibers, as shown in 1.5 and M-K1.5), and five HPHFRC mixes . The “K” in the mix names represents Kevlar, “G” represents glass, and “HF” represents hybrid fibers. The subscript numbers in the mix names represent the percentages of fibers added by mass of cement, e.g., HF-G0.5K1 is a hybrid fiber mix with 0.5% glass fibers by mass of cement and 1% Kevlar fibers by mass of cement. The fiber combinations of all mixes are given in In addition to the control mix (CM) of high-performance concrete, high-performance fiber-reinforced concrete (HPFRC) and high-performance hybrid fiber-reinforced concrete (HPHFRC) mixes were also cast using the same mix design. Kevlar fibers (KF) and glass fibers (GF) with lengths of 35 and 25 mm, respectively, were added and hybridized at 1.5% by mass of cement to create HPFRC and HPHFRC . The KF length was selected to counter macro-cracks and the GF length was selected to counter micro-cracks. Eight mixes were cast in total, including one CM, two HPFRC  were cast for every test, giving a total of 72 cylinders. Three of them were used for the compression test, three for the splitting tensile test, and the remaining three for the density and water absorption test. For each concrete mix, three standard beams (100 mm × 100 mm × 450 mm) were also cast to study the flexural behavior. The tests conducted in this study along with the ASTM codes are given in 1.5 was reduced by 32% as compared to M-G1.5. From M-G1.5 to M-K1.5, the slump behavior was reduced due to the water absorption ability of the Kevlar fibers, while glass fibers on the other hand do not absorb water. The control mix was the most workable among the mixes. Special care was given to all fiber-reinforced and hybrid fiber-reinforced mixes when filling the molds.Slump values of the control mix along with high-performance hybrid fiber mixes and other fiber mixes are shown in 1.5, HF-G1.25K0.25, HF-G1K0.5, and HF-G0.75K0.75 increased by 7 kg/m3, 5.5 kg/m3, 2.5 kg/m3, and 1 kg/m3, respectively, as compared to CM. The increases in density were due to the addition of glass fibers, which have a greater density as compared to Kevlar fibers. The density levels of HF-G0.5K1, HF-G0.25K1.25, and M-K1.5 decreased by 1.5 kg/m3, 4 kg/m3, and 5.5 kg/m3, respectively, as compared to CM. Decreases in density were observed as the percentage of Kevlar fibers increased in the hybrid mixes. This was due to the lower density of Kevlar fibers as compared to glass fibers. The water absorption levels of concrete mixes are shown in The density values of the concrete mixes are shown in f′c were noted for M-G1.5, HF-G1.25K0.25, HF-G1K0.5, HF-G0.75K0.75, HF-G0.5K1, HF-G0.25K1.25, and M-K1.5 as compared to CM of 9.7%, 10.1%, 10.6%, 13.4%, 9.5%, 8.6%, and 9.4%, respectively. Significant increases in the compressive strength values of HPHFRC mixes were observed as compared to the CM and HPFRC mixes. This was due to the hybridization effect of the fibers. The failure modes under compressive loading for all specimens are shown in The 28 days compressive strength results for the concrete specimens are shown in 1.5, HF-G1.25K0.25, HF-G1K0.5, HF-G0.75K0.75, HF-G0.5K1, HF-G0.25K1.25, and M-K1.5 increased by 12.2%, 14.2%, 15.5%, 17.0%, 19.0%, 21.0%, and 22.6%, respectively. The elastic modulus of M-K1.5 increased by 9.2% as compared to M-G1.5. The elastic modulus values were calculated from the stress–strain curves shown in The elastic modulus (Ec) values of all concrete mixes are given in pre), is the area underneath the stress–strain curve from the beginning to peak stress. The energy absorbed after cracking, i.e., the compressive energy absorption post-peak (CEApost), is the area underneath the stress–strain curve from peak stress to failure stress. The summation of CEApre and CEApost is regarded as the total compression energy absorption (TCE). The toughness index during compression (C-TI) is the ratio of the total compressive energy absorption to the compressive energy absorbed pre-peak (TCE/CEApre). All of the described parameters under compression loading are shown in pre values of M-G1.5, HF-G1.25K0.25, HF-G1K0.5, HF-G0.75K0.75, HF-G0.5K1, HF-G0.25K1.25, and M-K1.5 were increased by 43.9%, 44.5%, 40.2%, 33.5%, 34.4%, 32.8%, and 32.5%, respectively, as compared to CM. For CEApost, as compared to CM, increases of 52.4%, 88.2%, 96.0%, 124.6%, 105.8%, 100.3%, and 72.6% were observed for M-G1.5, HF-G1.25K0.25, HF-G1K0.5, HF-G0.75K0.75, HF-G0.5K1, HF-G0.25K1.25, and M-K1.5, respectively. The highest CEApost value was observed for HF-G0.75K0.75, which may have been due to the hybridization effect of the fibers. The TCE values of M-G1.5, HF-G1.25K0.25, HF-G1K0.5, HF-G0.75K0.75, HF-G0.5K1, HF-G0.25K1.25, and M-K1.5 were increased by 46.3%, 56.6%, 55.6%, 58.6%, 54.1%, 51.4%, and 43.6%, respectively, as compared to CM. The highest TCE value was observed for HF-G0.75K0.75. It is noted that the C-TI values of M-G1.5, HF-G1.25K0.25, HF-G1K0.5, HF-G0.75K0.75, HF-G0.5K1, HF-G0.25K1.25, and M-K1.5 increased by 1.6%, 8.3%, 11.0%, 18.8%, 14.6%, 14.0%, and 8.3%, respectively, as compared to CM. The percentages for f′c, CEApre, CEApost, TCE, C-TI, and Ec are given in The energy absorbed before cracking, i.e., the compressive energy absorption pre-peak . The toughness index during flexural loading (F-TI) is ratio of the total flexural energy absorption to flexural energy absorbed pre-peak (TFE/FEApre). All described parameters under compression loading are shown in pre values of M-G1.5, HF-G1.25K0.25, HF-G1K0.5, HF-G0.75K0.75, HF-G0.5K1, HF-G0.25K1.25, and M-K1.5, respectively. The highest FEApre was observed for M-K1.5. The FEApost for CM was observed to be zero because it failed after the first crack and could not absorb energy after the maximum load. Therefore, the increases in the FEApost values of HF-G1.25K0.25, HF-G1K0.5, HF-G0.75K0.75, HF-G0.5K1, HF- G0.25K1.25, and M-K1.5 specimens equaled 4.6%, 6.5%, 9.0%, 13.4%, 12.7%, and 8.3%, respectively, as compared to M-G1.5, which was increased by 100% as compared to CM.The flexural strength (ƒᵣ) values of the beam specimens tested on the 28th day of curing are shown in post value was noted for HF-G0.5K1. The increases in TEF as compared to CM were 407.9%, 422.5%, 434.2%, 444.7%, 454.3%, 465.6%, and 470.1% for concrete specimens of M-G1.5, HF-G1.25K0.25, HF-G1K0.5, HF-G0.75K0.75, HF-G0.5K1, HF-G0.25K1.25, and M-K1.5, respectively. The highest TEF value was noted for M-K1.5. For F-TI values, increases of 127.0%, 131.9%, 130.6%, 131.9%, 138.8%, 130.4%, and 117.3% were observed for concrete specimens of M-G1.5, HF-G1.25K0.25, HF-G1K0.5, HF-G0.75K0.75, HF-G0.5K1, HF-G0.25K1.25, and M-K1.5, respectively, as compared to CM. The highest F-TI value was observed for HF-G0.5K1. A percentage comparison of the concrete properties under the influence of flexural loading is shown in The highest FEAfs) values of cylindrical specimens are shown in fs for M-G1.5, HF-G1.25K0.25, HF-G1K0.5, HF-G0.75K0.75, HF-G0.5K1, HF-G0.25K1.25, and M-K1.5 as compared to CM were observed to be 26.5%, 27.5%, 29.3%, 27.8%, 28.5%, 27.3%, and 25.9%, respectively. The highest fs was observed for the HF-G1K0.5 specimen, which was a hybrid fiber mix. The failure modes under splitting tensile loading for all specimens are shown in The splitting tensile strength (pre) is the area underneath the load–time curve from the beginning to the peak load. The splitting tensile energy absorption post-peak (SEApost) is the area underneath the load–time curve from the peak load to the failure load. The summation of the SEApre and SEApost values is regarded as the total splitting tensile energy absorption (TSE). The splitting tensile failure modes of the specimens are shown in pre). The SEApre, SEApost, TSE, and S-TI values for the concrete specimens are given in pre for M-G1.5, HF-G1.25K0.25, HF-G1K0.5, HF-G0.75K0.75, HF-G0.5K1, HF-G0.25K1.25, and M-K1.5 as compared to CM were observed to be 72.3%, 86.4%, 97.4%, 84.1%, 97.4%, 99.6%, and 101.9%, respectively. The highest SEApre was noted for M-K1.5. The decreases in SEApost for HF-G1.25K0.25 and HF-G1K0.5 equaled 1.5% and 1.8%, respectively, as compared to M-G1.5. For SEApost, the increases for HF-G0.75K0.75, HF-G0.5K1, HF-G0.25K1.25, and M-K1.5 equaled 6.4%, 6.5%, 12.9%, and 19.0%, respectively. The highest value was observed for M-K1.5. The increases in TSE for M-G1.5, HF-G1.25K0.25, HF-G1K0.5, HF-G0.75K0.75, HF-G0.5K1, HF-G0.25K1.25, and M-K1.5 as compared to CM equaled 144.9%, 157.9%, 168.7%, 161.3%, 174.7%, 181.6%, and 188.4%, respectively. The increases in S-TI for M-G1.5, HF-G1.25K0.25, HF-G1K0.5, HF-G0.75K0.75, HF-G0.5K1, HF-G0.25K1.25, and M-K1.5 as compared to CM equaled 42.2%, 38.4%, 36.1%, 42.0%, 39.2%, 41.1%, and 42.8%, respectively. The highest S-TI was noted for M-K1.5. A percentage comparison of the concrete specimens under splitting tensile loading is given in The splitting tensile energy absorption pre-peak  increased by 14.6%, 11.8%, 35.0%, 15.9%, 37.9%, 81.6%, 56.9%, 21.7%, 61.7%, and 29.6%, respectively, as compared to CM. The results for HF-G0.75K0.75 were the best, as shown in 1K0.5, HF-G0.75K0.75, and HF-G0.5K1). These mixes can be used for rehabilitation work. Based on the above results, hybrid fiber concrete can be used in rehabilitation because of its enhanced mechanical properties in comparison to fiber-reinforced concrete. A comparison of the properties of HFRC with FRC is given in The optimization of concrete mixes is shown in R2 values ranged from 0.66 to 0.84 and the maximum variance observed between experimental and numerical values was 12%, as shown in The toughness index shows the energy absorption of a material post-fracture, which is given primary importance when choosing a material for rehabilitation. The empirical equations (Equations (1)–(3)) for predicting toughness indexes  were developed for fiber percentages by using experimental data from compressive, flexural, and splitting tensile strength tests. The For the compression toughness index:For the flexural toughness index:For the splitting tensile toughness index:Significant enhancements in the overall properties of high-performance hybrid fiber-reinforced concrete (HPHFRC) were observed as compared to high-performance fiber-reinforced concrete (HPFRC) and the control mix (CM), proving the usefulness of the fiber hybridization method in the concrete industry. In the rehabilitation of concrete bridges and structures, these enhancements can be put to use.The workability of concrete was significantly reduced with the addition of fibers. As the percentage of Kevlar fibers increased in the concrete, the workability decreased due to the water absorption of Kevlar fibers;1.5, HF-G1.25K0.25, HF-G1K0.5, HF-G0.75K0.75), because glass fibers are denser than Kevlar fiber. A correlation with the minimum water absorption was also observed in glass-fiber-dominant mixes. This was due to the water absorption properties of the Kevlar fibers;The maximum density was observed for mixes with dominant glass fiber percentages (M-G0.75K0.75) with 0.75% of glass fibers and 0.75% of Kevlar fibers. Among all mixes, the most dominant properties were for the HF-G0.75K0.75 mix due to the equal quantities of fibers exhibiting the best synergetic effect;The overall best properties were observed for the hybrid mix ;The high-performance hybrid fiber-reinforced concrete illustrated the best performance as compared to the CM and HPFRC mixes. The top three mixes that showed the best properties were hybrid fiber-reinforced concrete mixes (HF-GBased on these conclusions, the hybrid fiber mixes demonstrated more enhanced overall properties as compared to FRCs. These improved mechanical properties of the HFRC can be utilized in the rehabilitation of bridges and structures.The following are some of the conclusions extracted from this study:A long-term durability study of HPHFRC for rehabilitation needs to be performed.The chemical resistance should be evaluated before the practical implementation of the HFRC.Fibers of different length should be used to check their hybridization effects.To improve the mix’s workability, different super plasticizers need to be checked to identify the best results.A cost analysis is recommended before any commercial application.