The Etiology and Antimicrobial Susceptibility of Community-Onset Urinary Tract Infections in a Low-Resource/High-Resistance Area of Latin America

Urinary tract infections (UTIs) are common and are typically treated empirically, based on local antimicrobial resistance (AMR) data, which are often scarce in low- and middle-income countries. This study examines the AMR patterns of pathogens causing community-onset (CO) UTIs in the Bolivian Chaco. Urine samples were collected from subjects with suspected CO-UTIs and analyzed by culture techniques. Significant isolates were tested for their antimicrobial susceptibility. Additionally, <i>bla</i>_CTX-M and <i>mcr</i> genes were searched for using real-time PCR. A total of 361 CO-UTI episodes were diagnosed among 731 subjects from February 2020 to November 2021. The cases included uncomplicated and complicated UTIs (58.2% and 41.8%, respectively), with females accounting for the majority (85.3%) of cases. <i>Escherichia coli</i> was the most prevalent pathogen (86.6%), followed by <i>Klebsiella pneumoniae</i> (5.4%) and <i>Proteus</i> spp. (2.2%). Very high resistance rates (>50%) were observed for ampicillin, trimethoprim-sulfamethoxazole and fluoroquinolones, high resistance rates (>20%) for amoxicillin-clavulanate, third-generation cephalosporins and gentamicin, while lower resistance rates (<10%) were observed for nitrofurantoin and fosfomycin. The prevalence of <i>bla</i>_CTX-M among <i>E. coli</i> was high (26.7%). Colistin resistance was detected in 3.4% of <i>E. coli</i>, mostly associated with <i>mcr</i> genes. CO-UTIs from this area were characterized by high resistance rates to commonly used antibiotics (trimethoprim-sulfamethoxazole, amoxicillin-clavulanic acid and ciprofloxacin), highlighting the importance of knowledge of the local epidemiology to inform the selection of appropriate empirical antibiotic regimens.