Unraveling the resistance puzzle: Antibiotic susceptibility and genetic insights into extra-intestinal E. coli Strains in UTIs.

Abstract

Objective: To investigate the antibiotic resistance patterns and genetic factors associated with ExPEC strains isolated from UTI patients. Study Design: Cross sectional Study. Setting: Microbiology Lab in Lahore, Pakistan. Period: December 2021 to June 2022. Methods: A total of 300 urine samples were collected from patients with UTIs, sourced from various hospitals and labs. E. coli identification was confirmed using biochemical tests and the API 20 E standardized method. Results: Antimicrobial susceptibility testing was performed using the disc diffusion technique following CLSI guidelines. The findings revealed varying levels of resistance among the isolates. High resistance rates were observed for ampicillin (92.6%), amoxicillin (93.6%), ceftriaxone (88.9%), and ciprofloxacin (82.4%). Lower resistance rates were found for gentamycin (66%), meropenem (8.2%), tigecycline (4%), imipenem (12.4%), and colistin (0.0%). However, no significant association was detected between the AER gene and fluoroquinolone resistance. Conclusion: This study sheds light on the prevalence of antibiotic resistance in ExPEC strains causing UTIs. The high resistance rates to commonly prescribed antibiotics highlight the need for judicious antibiotic use and alternative treatment strategies. Moreover, the absence of a clear link between the AER gene and fluoroquinolone resistance suggests the involvement of other mechanisms in conferring resistance. Understanding the resistance patterns and genetic factors associated with ExPEC strains is crucial for devising effective treatment strategies and combating the growing problem of multi-drug resistance in UTIs caused by E. coli.