Phylogenetic Grouping and Virulence Characterization of ESBL-Producing and Non-Producing Vaginal Escherichia Coli

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The initial colonization of the vaginal mucosa with Escherichia coli is considered as a critical step toward urinary tract and neonatal infections. This study was conducted to characterize ESBL-producing (n=40) vaginal E. coli isolates from pregnant and non-pregnant women. These isolates were compared with corresponding ESBL-non-producing E. coli isolates (n=21). Both groups were investigated using PCR-based protocols for their phylogenetic origin and virulence genotype. High numbers of ESBL producers and non-producers were from group B2 (47.5% vs. 42.8%, respectively). None of ESBL non-producers clustered in group D, whereas significant numbers (P ≤ 0.05) of them belonged to group B1 (33.3%) in comparison with 20.0% and 7.5% of ESBL producers, respectively. Significant differences in the prevalence of this study included virulence factors were not observed between these two groups. In both high rates of multiple virulence factors possession were demonstrated among isolates belonged to groups B2 and D. Comparison of CTX-M-producers with non-CTX-M-ESBL-producers and ESBL-non-producers revealed no significant differences among these three groups. In total, 60.8%, 17.3%, 17.3% and 4.3% of multidrug resistant (MDR) isolates clustered in groups B2, D, A and B1, respectively. All MDR-ESBL-non producers (100%) belonged to phylogroup B2 compared with 50% of MDR ESBL-producers and their virulence was much more higher. This study indicates that significant differences are not present between ESBL-producing and non-producing vaginal E. coli for both phylogenetic group distribution and virulence genes possession. Also, ESBL-producing vaginal E. coli, especially CTX-M producers, tend to be more dominant among the highly virulent phylogroup B2 and to a lesser extent group D. These data reveal the importance of vaginal colonization by these highly virulent, MDR, ESBL-producing E. coli as a source of extraintestinal E. coli infections.