Antibiotic Resistance Pattern and Prevalence of Virulence Factors among ESBLs-producing Escherichia coli Isolates Causing Urinary Tract Infections

 Urinary tract infections (UTIs) pose a significant global health threat, primarily attributed to bacteria producing extended-spectrum beta-lactamases (ESBLs), with limited treatment options available. The specific genotypes of ESBL-producing strains remain largely unexplored in Guilan (northern Iran). Hence, the objective of this study was to determine the prevalence of ESBL-producing extra-intestinal pathogenic Escherichia coli (ExPEC) among hospitalized patients in this area.

 In this descriptive cross-sectional study, 269 isolates were examined phenotypically for ESBL production. All ESBLs producing isolates were screened for the presence of virulence and housekeeping genes by polymerase chain reaction (PCR) using specific primers. The antimicrobial susceptibility patterns were determined using the disk diffusion method according to the CLSI recommendation.

 Out of the 269 E. coli isolates, 107 cases (39.8%) were identified as producers of ESBLs. Antibiotic susceptibility testing conducted on the ESBL-producing isolates revealed the highest levels of resistance to cefotaxime, ampicillin, amoxicillin-clavulanate, cephalothin, cefixime, and ceftriaxone (100.0%). Nalidixic acid exhibited a resistance rate of 91.6%, followed by ceftazidime at 84.1%. On the other hand, the isolates showed the highest susceptibility to imipenem (94.4%), followed by nitrofurantoin (87.9%) and gentamicin (63.9%).

 The frequency of ESBL-producing ExPEC isolated from UTIs is concerning in Guilan. The most suitable antibiotic with the lowest risk of resistance for the patient can be prescribed using the updated susceptibility and resistance patterns of the bacteria.