Isolation and molecular characterization of multi-drug resistant uropathogenic Escherichia coli from urine samples: Insights into urinary tract infection management

Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) present a significant global health burden. With UPEC responsible for approximately 90 % of UTIs, understanding its mechanisms of virulence and antibiotic resistance is paramount for effective treatment strategies. This study aimed to investigate the prevalence of multi-drug resistant (MDR) E. coli strains in urinary tract infections and to elucidate the molecular mechanisms underlying their resistance. A total of 150 E. coli isolates were obtained from urinary tract infection specimens collected patients at Doctor’s Diagnostic Centre in Kalyan Nagar, Bangalore over four months November 2022 to February 2023. Isolation and screening of pathogenic E. coli were conducted using Eosin Methylene Blue Agar and Nutrient Agar, followed by identification through gram staining and biochemical characterization tests. Antibiotic susceptibility testing was performed using Mueller-Hinton agar and various antibiotic discs. Phenotypic and molecular identification of extended-spectrum beta-lactamase (ESBL) producers were conducted, along with the screening for specific antibiotic resistance genes using polymerase chain reaction (PCR). Of the 150 E. coli isolates, 57.3 % were found to be multi-drug resistant, with all 35 isolates from hospitalized patients exhibiting MDR characteristics. Phenotypic and molecular analyses revealed the presence of ESBL-producing isolates, with the blaCTX-M, blaTEM, and blaSHV genes detected in PCR assays. Plasmid extraction and PCR assays further identified the presence of plasmid-encoded carbapenemase genes (blaOXA-48, blaNDM-1, blaKPC-2), as well as other antibiotic resistance genes including those conferring resistance to fluoroquinolones. The results underscore the alarming prevalence of MDR E. coli strains in urinary tract infections, particularly in hospitalized patients. Molecular characterization revealed the diverse genetic mechanisms contributing to antibiotic resistance, including the presence of ESBLs and plasmid-encoded resistance genes. These findings emphasize the urgent need for surveillance and infection control measures to mitigate the spread of MDR pathogens and the development of alternative therapeutic strategies to combat antibiotic resistance in UTIs.