Analysis of phylogroups, biofilm formation, virulence factors, antibiotic resistance and molecular typing of uropathogenic Escherichia coli strains isolated from patients with recurrent and non-recurrent urinary tract infections.

Abstract

Background: Uropathogenic Escherichia coli (UPEC) is the predominant cause of urinary tract infections (UTIs), and the recurrence of these infections poses significant treatment challenges.

Objective: This study aimed to compare the phylogroups, biofilm formation, virulence factors, and antibiotic resistance of UPEC strains in patients with recurrent versus non-recurrent UTIs in Hamadan City, Western Iran.

Materials and methods: A total of 110 E. coli isolates were collected from urine cultures across three major hospitals and laboratories. The isolates were confirmed through biochemical tests, and their antibiotic resistance profiles were evaluated using the disk diffusion method. Biofilm production was assessed using the microtiter plate method, while virulence genes and phylogroup determination were analyzed via PCR. Real-time PCR was employed to compare the expression levels of the pap and fimH virulence genes.

Results: The results indicated that 73% of isolates were from non-recurrent UTI patients, with a higher incidence in females and children under 10 years. A significant difference was detected in the underlying diseases and the expression of the pap between the recurrent and non-recurrent groups. Antibiotic resistance was notably significant, particularly against Ampicillin-sulbactam, Trimethoprim-Sulfamethoxazole, Nalidixic acid, and Ciprofloxacin, with 77% of strains classified as multi-drug resistant (MDR). Despite differences in the rates of ESBL production between recurrent (53%) and non-recurrent (42.5%) strains, no significant differences were observed in antibiotic resistance, biofilm formation, virulence factors, or phylogroups between the two groups. Phylogenetic analysis revealed a predominance of phylogroups B2 and D, with high genetic diversity among the isolates.

Conclusion: The study highlights the traits of UPEC strains in recurrent and non-recurrent UTIs, showing high antibiotic resistance and genetic diversity among isolates. The study found notable differences in underlying diseases and the expression of the pap gene between recurrent and non-recurrent groups, suggesting that these factors may play a crucial role in the recurrence of infections. Further investigation into these differences could enhance our understanding and management of recurrent UTIs.