Molecular characterization of ESBL, AmpC genes and plasmid profiles in E. coli and K. pneumoniae isolates from urinary tract infections

Background Extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamases are major contributors to antimicrobial resistance in Escherichia coli and Klebsiella pneumoniae isolated from urinary tract infections (UTIs). This study aimed to investigate the prevalence and molecular characteristics of ESBL and AmpC genes in uropathogenic E. coli and K. pneumoniae from two distinct healthcare settings. Methods The isolates were identified and screened phenotypically for ESBL and AmpC production. The presence of resistance encoding genes was confirmed using PCR. The plasmid profile was also determined. The distribution of resistance determinants was analyzed in relation to the healthcare setting. Results Of the 385 UTI cases, 298 (77.4%) were healthcare-associated (HA-UTIs) and 87 (22.6%) were community-acquired (CA-UTIs). Age-wise distribution differed significantly ( p < 0.0001), with the 21-30-year group comprising 56% of cases. Females accounted for 63.3% of infections ( p = 0.0035). HA-UTIs were commonly associated with several patient-related risk factors. Higher frequencies of HA-UTIs were observed among catheterized patients (54%), post-hysterectomy patients (64%), post-cesarean section patients (27.2%), and patients with underlying conditions such as benign prostatic hyperplasia (38%), renal calculi (67%), and renal tumors (34%). Significant bacterial growth was detected in 291 (76%) urine samples, with E. coli (65%) as the most frequently isolated organism, followed by K. pneumoniae (30%). ESBL production was detected in 199 (73.4%) isolates, while AmpC production was identified in 52 (19%) isolates. ESBL-producing isolates were more prevalent in HA-UTIs, particularly among E. coli and K. pneumoniae . Correlation analysis showed strong positive associations between ESBL production and HA-UTI risk factors ( r = 0.86–0.97; p < 0.05). The distribution of plasmid-mediated ESBL and AmpC encoding genes showed that ESBL (94%) and AmpC (93%) were plasmid mediated. Isolates were dominated by plasmid types IncF (FIB, FII) + IncI1 + IncY in ESBL producers. IncI1 and IncF were linked with AmpC producers. Conclusion The findings highlighted a high burden of ESBL and AmpC producers among UTI-causing isolates with distinct genetic patterns. These insights underscore the need for tailored antimicrobial stewardship and infection control measures across different healthcare sectors. Clinical trial number Not applicable.