COLONIZATION FACTORS OF ENTEROTOXIGENIC ESCHERICHIA-COLI (ETEC) FROM RESIDENTS OF NORTHERN EGYPT

Infection caused by enterotoxigenic Escherichia coli (ETEC) poses a se rious health problem to children in developing countries. Colonization of the small intestinal mucosa by ETEC strains is mediated by antigen ically specific fimbriae, also known as colonization factor antigens ( CFA). The importance of this study arises from reports that active and passive immunization with ETEC strains harboring CFAs induced protect ive immunity against diarrhea in animal models with preformed antibodi es. In humans, ETEC containing CFA/I, II, III and IV have been identif ied. The aim of this study was to define CFAs of ETEC isolated in Alex andria, Egypt. One hundred and seven ETEC isolates from 132 human resi dents in Alexandria, Egypt were isolated during a birth cohort study. ETEC isolates were screened for heat labile (LT) and heat stable (ST) toxins using a P-32 oligonucleotide hybridization probe and a GM1 ELIS A. These isolates were examined using monoclonal antibodies against CP A/I, II, III, IV, and against the putative colonization antigens PCF01 59 and PCF0166, CS 7 and CS 17. CFAs were found in 48% of ETEC strains . CFA/I was found in 18% of the strains, CFA/II in 10% and CFA/IV in 1 4%. CFA III was not found. All fifteen strains expressing CFA/IV expre ssed CS6 and produced ST. CFA/IV was not found in non-ST producing str ains, while CFA/I was absent in ST - only producing strains.