Molecular Characterization and Antibiotic Resistance of Broad‐Spectrum β ‐Lactamase‐Producing Enterobacterales in Urinary Tract Infections in Libreville, Gabon

Background The effectiveness of antibiotic therapy for urogenital tract infections (UTIs) is increasingly compromised by the global dissemination of extended‐spectrum β ‐lactamase‐producing Enterobacterales (ES β L‐En). This study aimed to assess the involvement of broad‐spectrum β ‐lactamase‐producing Enterobacterales (BS β L‐En) in UTIs and to establish their antibiotic susceptibility profile. Methods A cross‐sectional study was conducted from October to December 2019 at the Army Training Hospital Omar Bongo Ondimba. All patients suspected of having a UTI were included. BS β L‐En isolates were recovered using MacConkey agar supplemented with cefotaxime. Phenotypic screening for β ‐lactamase (ES β L, AmpC, and carbapenemases) using specific phenotypic confirmatory disc diffusion test. Antimicrobial susceptibility was determined using the disk diffusion method and minimum inhibitory concentration (MIC) assays. The presence of resistance genes ( bla CTX-M , bla TEM , bla CARBA , bla IMP , mcr-1 and mcr-2 ) was investigated by polymerase chain reaction. Results A total of 295 patients were enrolled, among whom 18.3% (54/295) had UTIs. Of the isolated uropathogens 74.1% were BS β L‐En. The predominant species were Enterobacter cloacae (8/54, 14.8%), Escherichia coli (6/54, 11.1%) and Kluyvera spp (5/54, 9.3%). Among 40 BS β L‐En isolates, 87.5% ( n = 35/40) were confirmed by molecular analysis. Notably 48.5% (17/35) harbored at least two bla genes, simultaneously. Fourteen isolates carried the bla CARBA and bla IMP genes, which in combination with the bla CTX-M and bla TEM . About 40.0% of the isolates (14/35) carried the bla CTX-M , 8.6% had the bla TEM (3/35), and 2.9% had the bla IMP ( n = 1/35). All urinary isolates were multidrug‐resistant (MDR), exhibiting high levels of β ‐lactamase production, with resistance rates of 81.6 % ± 0.16 % for first‐line antibiotics (e.g., β ‐lactams, fluoroquinolones) and 61.7 % ± 0.04 % for last‐resort antibiotics (e.g., imipenen, ertapenem, and colistin). The prevalence of carbapenem resistance genes was 44.1%, whereas no colistin resistance genes ( mcr ‐1 and mcr ‐2) were detected. Conclusion This study highlights a high prevalence of multidrug‐resistant uropathogens producing BS β L, with significant resistance to both first‐line and last‐resort antibiotics.