Genotypic and Phenotypic Comparison of Enteroaggregative Escherichia coli Isolates from HIV-Positive and Non-HIV Diarrheal Samples

Abstract

Enteroaggregative Escherichia coli (EAEC) have been isolated from both HIV-positive and non-HIV diarrheal samples. In this study a collection of 18 isolates from these two groups were compared for biofilm formation and antibiotic resistance and for the presence of 14 virulence-related genes. All the HIV-positive and over 66% of the non- HIV strains were PCR-negative for adhesion-related sequences indicating that as yet unknown adhesins may play a role. However, despite some variations, the prevalence rate of the virulence-related genes was not significantly different in the two groups. HIV-positive isolates were biofilm producer but only a single weak biofilm former was observed among the non-HIV strains. The rate of resistance to most of the antibiotics used was higher among the HIV-positive group than the non-HIV isolates, but was significantly higher for amoxicillin-calvulanic acid (100%) and nalidixic acid (55.5%). Pulse field gel electrophoresis of the isolates produced 17 unique profiles reflecting the exiting heterogeneity of the isolates.

Recent advances in adherence and invasion of pathogenic Escherichia coli

“…The autotrasporter Pic has been defined as a gene marker associated with spreading of infection to the urinary tract (40). Finally, comparison of EAEC isolates from HIV-positive and non-HIV diarrheal samples showed that HIV-positive isolates are stronger biofilm producers and more resistant to antibiotics than the non-HIV diarrheal isolates, which confirmed the heterogeneity of the EAEC isolates (42). …”