Phylogenetic Grouping of Dominant Fecal Escherichia coli Isolates from Healthy Males and Females in Al-Kut/Wasit Province/Iraq

Abstract

Fecal isolates of Escherichia coli are divided into four main phylogenetic groups designated A, B1, B2 and D. Most commensal strains belong to group A and have fewer virulence factors than the extra intestinal pathogenic E. coli strains (ExPEC). This study was mainly designed for phylogenetic grouping of commensal fecal E. coli isolates from healthy males and females in Al-Kut City/Wasit Province/Iraq using PCR-based protocols. Also ExPEC's virulence genes were detected among these isolates. Among this study included isolates (n=205), group A was the most common among both females' and males' isolates (68.5% vs. 63.0%, respectively), followed by groups: B1 (15.7% vs. 22.6%, respectively), D (10.7% vs. 9.5%, respectively), and B2 (4.1% vs. 4.7%, respectively). Gender distribution of phylogenetic groups showed insignificant differences between females and males. Females' and males' isolates did not differ significantly for all of the detected ExPEC's virulence genes, except for papC which was significantly (P ≤ 0.05) more prevalent among males' isolates (16.6%) than among females' isolates (6.6%). In both females' and males' isolates the most prevalent virulence genes were fimH (97.5% vs. 100%, respectively) and iucC (52.0% vs. 55.9%, respectively), whereas the least prevalent were sfa/foc (0% each) and hly (0.82% vs. 0%, respectively). Furthermore, virulence genes were concentrated in isolates clustered in group B2. In both females and males, high percent of dominant commensal fecal E. coli isolates from Iraqi people in Al-Kut City clustered in phylogroup A followed by groups B1 and D whereas group B2 was rare. Also, dominant fecal strains with ExPEC characteristics were much less prevalent.