P3.H146: Antimicrobial Susceptibility of 687 Escherichia coli Isolates from Urinary Tract Infection in Brazil

Background: Escherichia coli is the most common urinary tract infection (UTI) etiology in both sexes. Initial treatment of UTI is often empirical. Therefore, choosing an appropriate antibiotic depends on knowing the antimicrobial susceptibility of the main uropathogens of UTI. This study aimed to describe the antimicrobial susceptibility of 687 E.coli isolates from UTI in a pediatric community teaching hospital in Brazil. In addition, we aim to monitor the prevalence of extended-spectrum beta-lactamase (ESBL)-producing E.coli.

Methods: We performed a retrospective 7-year observational study (2016–2022) of antimicrobial susceptibility of all UTIs due to E.coli, from patients younger than 15 years, diagnosed at the pediatric emergency department of the University Hospital of the University of Sao Paulo, Brazil. UTI was defined as bacteriuria of a single species of at least 50,000 colony-forming units (CFU)/mL in a catheter sample or at least 100,000 CFU/mL in a midstream sample.

Results: The figure 1 shows the antimicrobial susceptibility of 687 isolated E.coli. We found 4.4% ESBL-producing E. coli. Decreased susceptibility rates were found for ampicillin (42%), cefalotin (50%), cotrimoxazole (67%), and nalidixic acid (78%). E.coli is still highly susceptible to amoxicillin-clavulanate (84%), piperacillin-tazobactam (95%), second-generation cephalosporin (cefuroxime axetil-91%, cefuroxime-94%), third-generation cephalosporin (ceftriaxone-95%), fourth-generation cephalosporin (cefepime-96%), aminoglycoside (gentamicin-93%, amikacin-99%), carbapenems (meropenem-100%, ertapenem-100%), nitrofurantoin (97%), fosfomycin (100%) and fluoroquinolones (norfloxacin-88%, ciprofloxacin-90%).

Conclusion: E.coli isolates from Brazilian patients younger than 15 years old with UTI have low susceptibility to cotrimoxazole, ampicillin, cefalotin, and nalidixic acid. Second-generation cephalosporins and amoxicillin-clavulanate are appropriate empiric antibiotic choices to treat uncomplicated febrile UTIs. Nitrofurantoin and fosfomycin are suitable oral alternatives to treat uncomplicated non-febrile UTIs. Parenteral aminoglycosides, piperacillin-tazobactam, and third or fourth-generation cephalosporins should be considered for empiric treatment of patients with complicated UTI.