Enteroaggregative Escherichia coli as a Potential Cause of Diarrheal Disease in Adults Infected with Human Immunode®ciency Virus

Stools of 68 human immunodeficiency virus (HIV)–infected adults with diarrhea and 60 without diarrhea were examined for enteroaggregative Escherichia coli (EAggEc) by HeLa cell adherence assay. EAggEc were present in stools of 30 patients with and 18 without diarrhea (P .05). CD4 cell counts of patients with EAggEc and diarrhea were significantly lower than those of patients with EAggEc without diarrhea (P .02). There was no difference in the mean duration of diarrheal symptoms or in the number of stools per day between patients with EAggEc and those without. None of the EAggEc strains were positive by polymerase chain reaction for adherence fimbria, but 11 strains were positive for EAggEc heat-stable toxin EAST/1. Of the EAggEc strains, 51 % were resistant to trimethoprim-sulfamethoxazole and 65 % were resistant to ampicillin. EAggEc may be a pathogen in HIV-infected patients with diarrhea; HIV-infected patients with EAggEc appear to be more symptomatic when HIV disease is more advanced. Enteroaggregative Escherichia coli (EAggEc) have been as- ally, some strains have been shown to produce a larger protein toxin that activates interleukin-8 [16]. Additional strains havesociated with persistent diarrheal disease in children in the demonstrated the ability to invade HeLa or intestinal cell cul-developing world [1±6]. The mechanisms by which these or-tures and subvert cellular tyrosine phosphorylation or produceganisms cause diarrheal disease are not well understood. Vari