Correlation Between Prevalence of Some Colibactin Genes, Biofilm Formation, and Antimicrobial Resistance in Uropathogenic E. coli in Iraq

Colibactin is a genotoxin produced by Enterobacteriaceae via a polyketide synthase (pks) island cluster. There is less knowledge regarding the distribution of colibactin genes in E. coli isolates in Iraq and its correlation with biofilm and antibiotic susceptibility. Therefore, this study aimed to investigate the frequency of some colibactin genes (CIbA and CIbQ) in uropathogenic E. coli in Iraq and evaluate the correlation with biofilm and antimicrobial resistance. Between October 2023 and January 2024, 70 E. coli isolates were isolated from 120 females diagnosed with UTIs. Isolates were identified first by biochemical methods and confirmed molecularly by amplification of 16S rRNA gene with specific primers. PCR was employed to detect the CIbA and CIbQ genes. Biofilm production was assessed by the microtiter plates method, and antibiotic susceptibility was determined by the disc diffusion method. Results indicate a high prevalence of pks+ E. coli (40%, 28/70) compared to pks- E. coli (60%, 42/70) with non-significant differences (p > 0.05). E. coli produce different levels of biofilm with significant differences (p < 0.05). However, a statistically significant correlation has been found between E. coli (pks+) and a moderate biofilm formation with a significant difference (p < 0.05). pks+ E. coli isolates are more sensitive to all antibiotics under investigation, with a significant relation to fluoroquinolone group. Interestingly, current and previous results show that pks+ E. coli prevalence in Iraq has gradually increased over the last five years. High rates of pks-positive isolates in Iraqi urinary tract infections indicate the spread of highly genotoxic isolates.