Molecular and antimicrobial resistance characterization of E. coli causing nosocomial UTIs in Sohag University Hospitals

Background: Nosocomial urinary tract infections (NUTIs) are among the most prevalent healthcare-associated infections worldwide, with Escherichia coli (E. coli) being the most common causative agent. The increasing resistance of E. coli to multiple antibiotics, particularly through the production of extended-spectrum β-lactamases (ESBLs) and fluoroquinolone resistance genes presents a serious therapeutic challenge. Aim: This study aimed to characterize phenotypic, genotypic, and antimicrobial resistance profiles of E. coli isolates causing NUTIs at Sohag University Hospitals, Egypt. Methods: 100 E. coli isolates were recovered from hospitalized patients diagnosed with NUTIs. Antimicrobial susceptibility was tested using the modified Kirby-Bauer disc diffusion method in accordance with CLSI guidelines. Phenotypic ESBL production was assessed using the double-disc synergy test. Genotypic detection of ESBL-associated genes (blaCTX-M and blaTEM), quinolone resistance genes (qnrB, qnrS), and virulence genes (fimH and hlyA) was performed using polymerase chain reaction (PCR). Results: High levels of multidrug resistance (MDR) (85%) and extensive drug resistance (XDR) (13 %) were observed. Phenotypic ESBL production was detected in 50% of isolates. Genotypic analysis revealed blaCTX-M and blaTEM genes in 63% and 44% of isolates, respectively. Quinolone resistance genes qnrB and qnrS were found in 3 % and 89% of isolates. Virulence genes fimH and hlyA were present in 92% and 3 % of isolates, respectively. A significant association was observed between resistance gene presence and reduced susceptibility to key antimicrobials. Conclusion: E. coli isolates from NUTIs in this study showed alarming levels of resistance and widespread distribution of ESBL and quinolone resistance genes. Continuous surveillance, strict infection control measures, and molecular screening are essential to combat the spread of resistant uropathogens in hospital settings.