Phenotypic and genetic characterization of WHO prioritized extended-spectrum β-lactamase ESBL-producing gram-negative uropathogenic bacteria from Sulaymaniyah City, Iraq

Abstract Extended-spectrum β -lactamases (ESBLs) producing Gram-negative bacteria pose a critical global public health threat by limiting therapeutic options and complicating the treatment of urinary tract infections (UTIs). This study aimed to determine the phenotypic resistance profiles and genotypic determinants of ESBL-producing Gram-negative uropathogens isolated from catheterized patients in Sulaymaniyah City, Iraq. This cross-sectional study was conducted at Shar Hospital from 1st of February to 31st of May, 2025. A total of 100 Gram-negative bacteria were isolated from catheter-derived urine samples of UTI patients ( n = 168). Bacterial identification was performed using standard biochemical assays. Antimicrobial susceptibility was evaluated using the Kirby-Bauer disc diffusion method according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Phenotypic ESBL production was confirmed using the double-disc synergy test (DDST). Molecular detection of ESBL encoding genes ( bla TEM , bla SHV , and bla CTX-M ) was conducted using multiplex polymerase chain reaction (PCR). Statistical analysis was performed using Statistical Package for the Social Sciences. Phenotypic testing confirmed ESBL production in 32% (32/100) of the isolates, with E. coli serving as the primary producer (24/32). Carbapenems retained excellent activity overall, with 95% and 90% susceptibility to meropenem and imipenem, respectively. Genotypic screening of the 32 phenotypically confirmed ESBL producers revealed that bla TEM (90.6%, 29/32) and bla CTX-M (87.5%, 28/32) were the most prevalent determinants. Multigene carriage was common, dual carriage of bla TEM and bla CTX-M was observed in 56.3% (18/32) of the phenotypically confirmed ESBL isolates, and 25.0% (8/32) exhibited triple gene carriage ( bla TEM , bla CTX-M , and bla SHV ), all among E. coli isolates. No statistically significant associations were detected between individual gene-family carriage and the susceptibility phenotypes of the 12 tested antibiotics (all raw P > 0.05; all Holm-adjusted P = 1.000). A total of 25.0% (8/32) exhibited triple gene carriage ( bla TEM , bla CTX-M , and bla SHV ), all among E. coli isolates. The significant prevalence of ESBL-producing uropathogens in Sulaymaniyah is largely driven by E. coli showing multiplexed resistance genes, specifically bla TEM and bla CTX-M . These findings underscore the urgent need for rigorous antimicrobial stewardship programs, ongoing molecular surveillance, and prompt updates to current urinary tract infection (UTI) treatment guidelines to ensure the implementation of effective definitive therapies.