Distribution of acquired carbapenemase genes among uropathogenic Escherichia coli

Antibacterial resistance (ABR) and the dissemination of acquired resistance genes (ARGs), particularly acquired carbapenemase genes (ACGs), have intensified the burden of difficult-to-treat infections such as urinary tract infections (UTIs). This study aimed to determine the prevalence of key ACGs, including bla_DIM, bla_GIM, bla_IMP, bla_NDM, bla_SIM, bla_SPM, bla_VIM, bla_AIM, bla_BIC, bla_KPC, and bla_OXA-48, and to establish gene distribution profiles among uropathogenic Escherichia coli (UPEC) strains.

A total of 105 UPEC-positive urine samples were collected between August 2023 and January 2024. Isolates were confirmed using standard microbiological and biochemical methods. Antibacterial susceptibility testing (AST) was performed via the Kirby-Bauer disc diffusion method. The presence of ACGs was assessed by polymerase chain reaction (PCR), and results were analyzed using chi-square and Fisher's exact tests.

Resistance and gene distribution profiles were established, including multidrug-resistant (MDR), extensively drug-resistant (XDR), and pandrug-resistant (PDR) patterns. The most prevalent ACGs were, respectively, bla_SPM (82.86%), bla_GIM (20.00%) and bla_VIM (16.19%). Nine isolates (8.57%) lacked ACGs, while the bla_SPM profile was predominant in 37 isolates (35.24%) and strongly associated with the highest ABR rates. Extended-spectrum β-lactamase (ESBL) production was detected in 38 isolates (36.19%). Overall, 75.24% of strains were MDR, 7.62% XDR, and 0.95% PDR.

The high prevalence of ACGs, e.g., bla_SPM and the rise of MDR, XDR, and PDR strains underscore the urgent need to reassess treatment strategies for UTIs. Novel therapeutic approaches and strategies are essential to control and reduce further resistance development.