Evaluation of Biofilm Formation Potential and Corresponding Virulence Genes in Uropathogenic E. coli Isolates from Kirkuk, Iraq

Abstract

Background: Urinary tract infections (UTIs) rank among the most prevalent extraintestinal infections in humans. Escherichia coli is the principal causative agent of urinary tract infections (UTIs), belongs to the Enterobacteriaceae family, and exists inside the normal microbiota of humans. Method: A cross-sectional study was undertaken at an institution with female patients, pregnant, non-pregnant, symptomatic and asymptomatic patients. At Kirkuk General Hospital, the Gynecology and Pediatric Hospital from September 2024 to December 2024. A mid-stream urine specimen was obtained using a clean-catch method, and significant isolates were identified by the VITEK2 system. Biofilm formation was phenotypically and genotypically investigated. Result: A total of 300 urine specimens, 49 (16.33%) were positive cultures for bacteria. Gram-negative bacteria were prevalent than gram-positive about 41 (83.67%). UPEC was the predominant gram-negative pathogen 27 (55.10%), Klebsiella pneumonia 5 (10.20%), Pseudomonas aeruginosa, Proteus mirabilis, Enterococcus faecalis, Enterobacter cloacae were 2 (4.08%). Biofilm production in UPEC estimated by micro-titer plate method, with the results were 1 (3.70%) strong, 9 (33.33%) moderate, 17 (62.96%) weak biofilm producers. Molecular analysis conducted via polymerase chain reaction (PCR) demonstrated that all of 27 UPEC (100%) strains obtained from females with UTIs had curli fimbria (csgA) and type 1 fimbriae (fimA) genes. Curli fimbria is recognized for its role in bacterial biofilm development and the adherence of E. coli associated with human cystitis. Hemolysin produced in 8/27 of UPEC isolates and hlyA gene was 100% in these isolates. Conclusion: About 20% of the positive cases were pregnant women. All UPEC isolates were biofilm producers and all of them expressed (csgA) and ( fimA) genes.