Sex, drugs, bugs, and age: Rational selection of empirical therapy for outpatient urinary tract infection in an era of extensive antimicrobial resistance

Development and validation of a parsimonious prediction model for positive urine cultures in outpatient visits

Urine culture is often considered the gold standard for detecting the presence of bacteria in the urine. Since culture is expensive and often requires 24-48 hours, clinicians often rely on urine dipstick test, which is considerably cheaper than culture and provides instant results. Despite its ease of use, urine dipstick test may lack sensitivity and specificity. In this paper, we use a real-world dataset consisting of 17,572 outpatient encounters who underwent urine cultures, collected between 2015 and 2021 at a large multi-specialty hospital in Abu Dhabi, United Arab Emirates. We develop and evaluate a simple parsimonious prediction model for positive urine cultures based on a minimal input set of ten features selected from the patient's presenting vital signs, history, and dipstick results. In a test set of 5,339 encounters, the parsimonious model achieves an area under the receiver operating characteristic curve (AUROC) of 0.828 (95% CI: 0.810-0.844) for predicting a bacterial count ≥ 105 CFU/ml, outperforming a model that uses dipstick features only that achieves an AUROC of 0.786 (95% CI: 0.769-0.806). Our proposed model can be easily deployed at point-of-care, highlighting its value in improving the efficiency of clinical workflows, especially in low-resource settings.

Virulence Genes Profile and Antimicrobial Susceptibility of Community-Acquired Bacterial Urinary Tract Infections in a Brazilian Hospital

Urinary tract infections (UTI) are one of the most common diseases worldwide and Escherichia coli is the most common causative bacteria. Empirical treatment is challenging due to antimicrobial or multidrug-resistance. The aims of this study were to determine the uropathogens and their antimicrobial susceptibility profile, as well as to identify the phylogroups and virulence genes of E. coli strains, associated with community-acquired UTI in outpatients admitted at a Brazilian Hospital in southeast Brazil. In total, 47 bacterial strains were isolated from 47 patients, 44 women and 2 men (no gender record from one patient). The age of the patients whose urine culture were positive varied from 0 (less than one month) to 104 years. Most of the isolates were E. coli (41/47), followed by Klebsiella pneumoniae (2/47), Klebsiella variicola/Klebsiella aerogenes (1/47), Pseudomonas aeruginosa (1/47), Proteus mirabilis (1/47), and Citrobacter koseri (1/47). Most E. coli strains were classified as phylogroup B2 (15/41 = 36.59%) and B1 (12/41 = 29.27%) and the most common virulence genes among E. coli strains were fimH (31/41 = 75.61%), iutA (21/41 = 51.22%), and tratT (16/41 = 39.02%). Among the E. coli strains, 59% were multidrug-resistance and strains that were ampicillin, sulfamethoxazole/trimethoprim, or tetracycline-resistant exhibited more chance to be multidrug-resistance, with an odds ratio of 100.00 [95% confidence interval (CI) 9.44-1059.26], 22.50 (95% CI 3.95-128.30), and 12.83 (95% CI 2.68-61.45), respectively. Our results showed that E. coli was the main etiological agent identified and demonstrated high frequency of multidrug-resistance and virulence factors in bacterial strains isolated from UTIs.

Carbapenem stewardship with ertapenem and antimicrobial resistance-a scoping review

Consumption of carbapenem has increased due to extended-spectrum beta-lactamase-producing bacteria spreading. Ertapenem has been suggested as a not carbapenem-resistance inducer. We performed a scoping review of carbapenem-sparing stewardship with ertapenem and its impact on the antibiotic resistance of Gram-negative bacilli. We searched PubMed for studies that used ertapenem as a strategy to reduce resistance to carbapenems and included epidemiologic studies with this strategy to evaluate susceptibility patterns to cephalosporins, quinolones, and carbapenems in Gram-negative-bacilli. The search period included only studies in English, up to February 2018. From 1294 articles, 12 studies were included, mostly from the Americas. Enterobacteriaceae resistance to quinolones and cephalosporins was evaluated in 6 studies and carbapenem resistance in 4 studies. Group 2 carbapenem (imipenem/meropenem/doripenem) resistance on A. baumannii was evaluated in 6 studies. All studies evaluated P. aeruginosa resistance to Group 2 carbapenem. Resistance profiles of Enterobacteriaceae and P. aeruginosa to Group 2 carbapenems were not associated with ertapenem consumption. The resistance rate of A. baumannii to Group 2 carbapenems after ertapenem introduction was not clear due to a lack of studies without bias. In summary, ertapenem as a strategy to spare use of Group 2 carbapenems may be an option to stewardship programs without increasing resistance of Enterobacteriaceae and P. aeruginosa. More studies are needed to evaluate the influence of ertapenem on A. baumannii.

A Clinical Perspective on the Antimicrobial Resistance Spectrum of Uropathogens in a Romanian Male Population

Considering urinary tract infections (UTIs), a significant public health problem with negligible recent research, especially on the male eastern European population, we aimed to determine the antimicrobial resistance rates of uropathogens for the most commonly used antibiotics in urological practice in our country. We conducted a multicenter retrospective study in two different teaching hospitals in Romania, analyzing urine samples from 7719 patients to determine the frequency of incriminating pathogens and their resistance to different antibiotics, in a comparative approach. We determined Escherichia coli (35.98%) to be the most common pathogen with the highest sensitivity to amikacin (S = 91.72%), meropenem (S = 97.17%) and fosfomycin (S = 86.60%) and important resistance to amoxicillin-clavulanic ac. (R = 28.03%) and levofloxacin (R = 37.69%), followed by Klebsiella spp. (22.98%) with the highest sensitivity to amikacin (S = 78.04%) and meropenem (S = 81.35%) and important resistance to amoxicillin-clavulanic ac. (R = 65.58%) and levofloxacin (R = 45.36%); the most frequent Gram-positive pathogen was Enterococcus spp. (19.73%) with the highest sensitivity for vancomycin (S = 93.75%) and fosfomycin (S = 87.5%) and considerable resistance to penicillin (R = 33.52%) and levofloxacin (R = 42.04%). The findings are an important tool in managing UTIs and should be acknowledged as reference research not only for clinicians from Romania but for all physicians treating male UTIs.

In Vitro Activity of Oral Antimicrobial Agents against Pathogens Associated with Community-Acquired Upper Respiratory Tract and Urinary Tract Infections: A Five Country Surveillance Study

Introduction

Bacterial infections that cause community-acquired urinary tract infections (CA-UTI) and upper respiratory tract infections (CA-URTI) are most frequently treated empirically. However, an increase in antimicrobial resistance has become a problem when treating outpatients.

Methods

This study determined the in vitro activities of oral antibiotics among 1501 pathogens from outpatients with CA-UTI and CA-URTI in medical centers during 2012 and 2013 from Argentina, Mexico, Venezuela, Russia, and the Philippines. Minimal inhibitory concentrations (MICs) were determined using broth microdilution and susceptibility defined by Clinical Laboratory Standards Institute (CLSI) and European Committee for Antimicrobial Susceptibility Testing (EUCAST) criteria.

Results

Ceftibuten (MIC₅₀, ≤0.25 mg/L) was more potent in vitro compared to other β-lactams against Enterobacteriaceae from CA-UTI. Susceptibility to fluoroquinolones using CLSI criteria varied: Argentina and Mexico (50%), the Philippines (60%), Venezuela (70%), and Russia (80%). Fosfomycin susceptibility was >90% against Enterobacteriaceae in each country. Susceptibility among Enterobacteriaceae to trimethoprim-sulfamethoxazole was 30.6–75.6% and nitrofurantoin susceptibility also varied among the countries and was higher when EUCAST breakpoints were applied (65–>90%) compared to CLSI (52–84%). All Haemophilus influenzae isolates from CA-URTI were susceptible to ceftibuten, cefixime, cefpodoxime, and cefuroxime using CLSI breakpoint criteria. EUCAST criteria produced intermediate and resistant MIC values for these oral cephalosporins. Country-specific susceptibility variation for fluoroquinolones, macrolides, and trimethoprim-sulfamethoxazole was observed among Streptococcus pneumoniae and Streptococcus pyogenes from CA-URTI.

Conclusion

This study demonstrated that antimicrobial susceptibility patterns varied in the five countries investigated among pathogens from CA-UTI and CA-URTI.

Funding

Merck & Co. Inc., Kenilworth, New Jersey, USA.

ANTIBIOTIC RESISTANCE PATTERNS OF URINARY TRACT INFECTIONS IN A NORTHEASTERN BRAZILIAN CAPITAL

Urinary tract infection is a common problem worldwide. Its clinical characteristics and susceptibility rates of bacteria are important in determining the treatment of choice and its duration. This study assessed the frequency and susceptibility to antimicrobials of uropathogens isolated from community-acquired urinary tract infections in the city of Natal, Rio Grande do Norte State capital, northeastern Brazil, from 2007 to 2010. A total of 1,082 positive samples were evaluated; E. coli was the most prevalent pathogen (60.4%). With respect to the uropathogens susceptibility rates, the resistance of enterobacteria to ciprofloxacin and sulfamethoxazole-trimethoprim was 24.4% and 50.6%, respectively. Susceptibility was over 90% for nitrofurantoin, aminoglycosides and third-generation cephalosporins. High resistance rates of uropathogens to quinolones and sulfamethoxazole-trimethoprim draws attention to the choice of these drugs on empirical treatments, especially in patients with pyelonephritis. Given the increased resistance of community bacteria to antimicrobials, local knowledge of susceptibility rates of uropathogens is essential for therapeutic decision making regarding patients with urinary tract infections.

Community-associated urinary infections requiring hospitalization: risk factors, microbiological characteristics and patterns of antibiotic resistance

OBJECTIVE

Although patients with urinary tract infections (UTIs) are usually managed as outpatients, a percentage of them requires hospitalization. To review risk factors and microbiological characteristics of community-associated UTIs (CAUTIs) requiring hospitalization has been our objective.

MATERIAL AND METHODS

A prospective observational study was carried out from November 2011 to December 2013. Incidence, microbiological characteristics and antibiotic resistance patterns in patients with CAUTIs that required hospitalization were analyzed. Risk factors (including diabetes mellitus, urolithiasis, urinary catheterization) and resistance rates of each pathogen were also analyzed.

RESULTS

Four hundred and fifty seven patients were hospitalized in our department with CAUTI. The mean age was 56.2±19.85 years. Of them, 52.1% patients were women, 19.7% had urinary indwelling catheter and 11.4% have had a previous UTI. The most frequently isolated pathogens were Escherichia coli (60.6%), followed by Klebsiella (9.2%), Enterococcus (8.4%) and Pseudomonas (7.2%). Enterobacteriaceae other than E.coli were more prevalent in male and older patients. On the other side the most frequently isolated pathogen in patients with a previous UTI and a urinary catheter was Entercoccus. The resistance rates E. coli against ampicillin/amoxicillin + β lactamase inhibitor was 23.5%, against third-generation cephalosporins 16.6%, against fluoroquinolones 31.3% and 16.7% against aminoglycosides. 11.4% E. coli strains were producers of extended-spectrum Beta-lactamases (ESBL). Finally, the resistance rates of Enterococcus and Pseudomonas against quinolones were of 50.0% and 61.5%, respectively.

CONCLUSIONS

CAUTIs that require hospitalization are most frequent in older age, male gender, and presence of urinary catheter, with urolithiasis and with previous episodes of UTI. These factors are also related to isolation of pathogens other than E. coli and higher resistance rates.

Pharmacodynamic profiling of commonly prescribed antimicrobial drugs against Escherichia coli isolates from urinary tract

Since antimicrobial resistance among uropathogens against current first line agents has affected the management of severe urinary tract infection, we determined the likelihood that antibiotic regimens achieve bactericidal pharmacodynamic exposures using Monte Carlo simulation for five antimicrobials (ciprofloxacin, ceftriaxone, piperacillin/tazobactam, ertapenem, and meropenem) commonly prescribed as initial empirical treatment of inpatients with severe community acquired urinary tract infections. Minimum inhibitory concentration determination by Etest was performed for 205 Brazilian community urinary tract infection Escherichia coli strains from 2008 to 2012 and 74 E. coli bloodstream strains recovered from a surveillance study. Pharmacodynamic exposure was modeled via a 5000 subject Monte Carlo simulation. All isolates were susceptible to ertapenem and meropenem. Piperacillin/tazobactam, ceftriaxone and ciprofloxacin showed 100%, 97.5% and 83.3% susceptibility among outpatient isolates and 98.6%, 75.7% and 64.3% among inpatient isolates, respectively. Against outpatient isolates, all drugs except ciprofloxacin (82.7% in aggressive and 77.6% in conservative scenarios) achieved high cumulative fraction of response: carbapenems and piperacillin/tazobactam cumulative fraction of responses were close to 100%, and ceftriaxone cumulative fraction of response was 97.5%. Similar results were observed against inpatients isolates for carbapenems (100%) and piperacillin/tazobactam (98.4%), whereas ceftriaxone achieved only 76.9% bactericidal cumulative fraction of response and ciprofloxacin 61.9% (aggressive scenario) and 56.7% (conservative scenario) respectively. Based on this model, standard doses of beta-lactams were predicted to deliver sufficient pharmacodynamic exposure for outpatients. However, ceftriaxone should be avoided for inpatients and ciprofloxacin empirical prescription should be avoided in both inpatients and outpatients with complicated urinary tract infection.

Antimicrobial resistance among Enterobacteriaceae in South America: history, current dissemination status and associated socioeconomic factors

South America exhibits some of the higher rates of antimicrobial resistance in Enterobactericeae worldwide. This continent includes 12 independent countries with huge socioeconomic differences, where the ample access to antimicrobials, including counterfeit ones, coexists with ineffective health systems and sanitation problems, favoring the emergence and dissemination of resistant strains. This work presents a literature review concerning the evolution and current status of antimicrobial resistance threats found among Enterobacteriaceae in South America. Resistance to β-lactams, fluoroquinolones and aminoglycosides was emphasized along with description of key epidemiological studies that highlight the success of specific resistance determinants in different parts of the continent. In addition, a discussion regarding political and socioeconomic factors possibly related to the dissemination of antimicrobial resistant strains in clinical settings and at the community is presented. Finally, in order to assess the possible sources of resistant bacteria, we compile the current knowledge about the occurrence of antimicrobial resistance in isolates in South American' food, food-producing animals and off-hospitals environments. By addressing that intensive intercontinental commerce and tourism neutralizes the protective effect of geographic barriers, we provide arguments reinforcing that globally integrated efforts are needed to decelerate the emergence and dissemination of antimicrobial resistant strains.

Resistant gram-negative infections in the outpatient setting in Latin America

Latin America has a high rate of community-associated infections caused by multidrug-resistant Enterobacteriaceae relative to other world regions. A review of the literature over the last 10 years indicates that urinary tract infections (UTIs) by Escherichia coli, and intra-abdominal infections (IAIs) by E. coli and Klebsiella pneumoniae, were characterized by high rates of resistance to trimethoprim/sulfamethoxazole, quinolones, and second-generation cephalosporins, and by low levels of resistance to aminoglycosides, nitrofurantoin, and fosfomycin. In addition, preliminary data indicate an increase in IAIs by Enterobacteriaceae producing extended-spectrum β-lactamases, with reduced susceptibilities to third- and fourth-generation cephalosporins. Primary-care physicians in Latin America should recognize the public health threat associated with UTIs and IAIs by resistant Gram-negative bacteria. As the number of therapeutic options become limited, we recommend that antimicrobial prescribing be guided by infection severity, established patient risk factors for multidrug-resistant infections, acquaintance with local antimicrobial susceptibility data, and culture collection.

A one-year prospective study on the antibiotic resistance of E. coli strains isolated in urinary specimens of children hospitalized at the University Pediatric Medical Center in Novi Sad, Serbia

PURPOSE

Urinary tract infections (UTIs), the most common serious bacterial infections in children, are frequently caused by Escherichia coli. The purpose of this study was to investigate E. coli resistance/multidrug resistance to antibiotics most frequently used for UTIs.

METHODS

Children 0-18 years of age, hospitalized at the University Pediatric Hospital in Novi Sad, Serbia, were included in a 1-year observational prospective study. The microbiological analysis was performed using the standard Kirby-Bauer disk diffusion method. The results were analyzed using WHONET 5.4 software.

RESULTS

E. coli was isolated from 61.7 % of positive urine specimens. In general, higher average E. coli antibiotic resistance was found in infants and toddlers compared to children and adolescents (33.4 vs. 25.0 %) (p < 0.0001). Furthermore, it was observed that the average resistance to all the tested antibiotics was higher in boys than in girls (37.0 vs. 25.1 %) (p < 0.0001). E. coli was highly susceptible to piperacillin/tazobactam (>93.1 %), amikacin (86.3 %), quinolones (>75.0 %), and penems (>96.6 %). The prevalence of multiresistant E. coli strains was significantly higher in infants and toddlers (72.3 vs. 36.8 %) (p < 0.0001).

CONCLUSIONS

E. coli, a common cause of UTIs in children admitted to pediatric hospitals, is highly resistant/multidrug-resistant to commonly used antibiotics. Higher average resistance is found in infants and toddlers than in children and adolescents, as well as in boys compared to girls. These findings are important for the regional empiric therapy of UTIs and call for actions to decrease E. coli antibiotic resistance.

The importance of gender-stratified antibiotic resistance surveillance of unselected uropathogens: a Dutch Nationwide Extramural Surveillance study

Few studies have been performed on urinary tract infections (UTIs) in men. In the present study, general practitioners (n = 42) from the Dutch Sentinel General Practice Network collected urinary samples from 560 male patients (≥ 18 years) suspected of UTI and recorded prescribed antibiotic treatment. In this way, the antibiotic susceptibility of Gram-negative uropathogens, including extended-spectrum beta-lactamase (ESBL-) producing Escherichia coli could be determined. In addition, E. coli susceptibility and antibiotic prescriptions were compared with data from a similar UTI study among women and with data collected 7 years earlier. Of 367 uropathogens (66%) identified (≥ 10(3) cfu/mL), most were Gram-negative (83%) and E. coli being isolated most frequently (51%). Antibiotic susceptibility to ciprofloxacin, norfloxacin and nitrofurantoin was 94%, 92% and 88%, respectively, whereas co-amoxiclav (76%) and co-trimoxazole (80%) showed lower susceptibilities. One ESBL (0.5%) was found. A significantly higher proportion of female UTIs was caused by E. coli compared with men (72% versus 51%, P<0.05). E. coli susceptibility tended to be lower in men compared with women, although not reaching statistical significance. No changes in E. coli susceptibility were observed over time (all P>0.05). Co-amoxiclav and nitrofurantoin prescriptions increased over time (11% versus 28% and 16% versus 23% respectively, both P<0.05), whereas co-trimoxazole prescriptions decreased (24% versus 14%, P<0.05). In conclusion, given the observed gender differences in uropathogen distribution and (tendency in) E. coli antibiotic susceptibility, empirical male UTI treatment options should be based on surveillance studies including men only. When awaiting the culture result is clinically not possible, fluoroquinolones are advised as first-choice antibiotics for male UTIs in Dutch general practices based on current antibiotic susceptibility data. The prevalence of ESBL-producers was low and no differences were observed in antibiotic susceptibility over a 7-year period. In addition, antibiotic prescriptions changed in accordance with national guidelines during this time period.