Prevalence of Escherichia coli K1 Rectovaginal Colonization Among Pregnant Women in Iran: Virulence Factors and Antibiotic Resistance Properties

Neonatal invasive infections caused by Escherichia coli K1 are still major health problems and effective preventive strategies at the maternal level can be a concern. The aim of this study was to determine the prevalence of rectovaginal colonization, related risk factors, virulence factors, and antibiotic resistance properties of E. coli K1 among pregnant women. In this cross-sectional study, vaginal and rectal swabs were collected from 400 pregnant women. The identification of E. coli isolates was performed by microbiological tests. A polymerase chain reaction (PCR) assay was used to identify the E. coli K1 strains. The antimicrobial susceptibility patterns were determined by the Kirby-Bauer disk diffusion. Two duplex PCR assays were developed separately to detect genes encoding virulence determinants (fimH, hlyF, ibeA, and iucC) in the E. coli strains. The vaginal and rectal maternal E. coli K1 colonization rates were 3.7% and 19.25%, respectively. There is no significant association between demographic-obstetric factors and vaginal E. coli colonization in pregnant women. The most effective antibiotics against E. coli K1 strains were imipenem, gentamycin, ciprofloxacin, and ceftazidime. In our study, the E. coli K1 strains were significantly more likely to possess the fimH (90.9% vs. 60.7%) and iucC (90.9% vs. 53.6%) than the E. coli non-K1 strains. This study demonstrates that E. coli K1 seems to be more virulent than non-K1 strains. Our findings highlight the importance of screening pregnant women for vaginal colonization by E. coli K1 and of the appropriate antibiotic prophylaxis for the prevention of early-onset E. coli neonatal infection and comorbidity.