Entamoeba histolytica Interaction with Enteropathogenic Escherichia coli Increases Parasite Virulence and Inflammation in Amebiasis [Fungal and Parasitic Infections]

In this study, we sought to determine if the interaction with enteropathogenic (EPEC) or nonpathogenic Escherichia coli (strain DH5α) could modify the virulence of E. histolytica to cause disease in animal models of amebiasis. In vitro studies showed a 2-fold increase in CaCo2 monolayer destruction when E. histolytica interacted with EPEC but not with E. coli DH5α for 2.5 h. This was associated with increased E. histolytica proteolytic activity as revealed by zymogram analysis and degradation of the E. histolytica CP-A1/5 (EhCP-A1/5) peptide substrate Z-Arg-Arg-pNC and EhCP4 substrate Z-Val-Val-Arg-AMC. Additionally, E. histolytica-EPEC interaction increased EhCP-A1, -A2, -A4, and -A5, Hgl, Apa, and Cox-1 mRNA expression. Despite the marked upregulation of E. histolytica virulence factors, nonsignificant macroscopic differences in amebic liver abscess development were observed at early stages in hamsters inoculated with either E. histolytica-EPEC or E. histolytica-E. coli DH5α. Histopathology of livers of E. histolytica-EPEC-inoculated animals revealed foci of acute inflammation 3 h postinoculation that progressively increased, producing large inflammatory reactions, ischemia, and necrosis with high expression of il-1β, ifn-, and tnf-α proinflammatory cytokine genes compared with that in livers of E. histolytica-E. coli DH5α-inoculated animals. In closed colonic loops from mice, intense inflammation was observed with E. histolytica-EPEC mani...
Source: Infection and Immunity - Category: Infectious Diseases Authors: Tags: Fungal and Parasitic Infections Source Type: research