Detection and prevalence of extended spectrum β-lactamases production among Enterobacteriaceae isolated from urinary tract infections

Urinary tract infections (UTIs) by extended-spectrum beta-lactamase producing Enterobacteriaceae (ESBL-E) have become an important public health problem with a substantial economic burden, as they lead to more complicated infections, longer duration of treatment, and increases in patient mortality. A total of 1267 urine samples were collected from patients during the period of 2018 to 2020. The isolates were identified based on colony morphology and biochemical tests. Antimicrobial susceptibility testing was done by modified Kirby Bauer disc diffusion method. Resistant isolates to third generation cephalosporins were tested for ESBL production by double-disk synergy test (DDST), DDST methods on MH agar plates supplemented with cloxacillin and by confirmatory double disk test (DDT). 400 strains causing UTIs were identified and classified as members of Enterobacteriaceae. The results of antimicrobial susceptibility tests showed that 68.5% (274/400) of the Enterobacteriaceae isolates were multi-drug resistant (MDR) strains. The overall prevalence of ESBL-E was 59.5% (238/400). The highest frequencies of ESBL-E were observed in internal medicine devices (68/400) and the highest ESBL production was observed in E. coli (85/238). The ESBL producing isolates were significantly resistant to penicillins and cephalosporins compared to non-ESBL producers. However, those ESBL-E strains were sensitive to imipenem (80.2%) and nitrofurantoin (87.8%). High levels of MDR strains and ESBL-E in our study highlights the need for applying specific infection control measures, and accordingly we urge physicians to opt for specific strategies for regular surveillance of uropathogenic bacteria.