Author(s): Qadri F, Das SK, Faruque AS, Fuchs GJ, Albert MJ,
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Abstract The prevalence of toxin types and colonization factors (CFs) of enterotoxigenic Escherichia coli (ETEC) was prospectively studied with fresh samples (n = 4,662) obtained from a 2\% routine surveillance of diarrheal stool samples over 2 years, from September 1996 to August 1998. Stool samples were tested by enzyme-linked immunoassay techniques and with specific monoclonal antibodies for the toxins and CFs. The prevalence of ETEC was 14\% (n = 662), with over 70\% of the strains isolated from children 0 to 5 years of age, of whom 93\% were in the 0- to 3-year-old age range. Of the total ETEC isolates, 49.4\% were positive for the heat-stable toxin (ST), 25.4\% were positive for the heat-labile toxin (LT) only, and 25.2\% were positive for both LT and ST. The rate of ETEC isolation peaked in the hot summer months of May to September and decreased in winter. About 56\% of the samples were positive for 1 or more of the 12 CFs that were screened for. The coli surface antigens CS4, CS5, and/or CS6 of the colonization factor antigen (CFA)/IV complex were most prevalent (incidence, 31\%), followed by CFA/I (23.5\%) and coli surface antigens CS1, CS2, and CS3 of CFA/II (21\%). In addition, other CFs detected in decreasing order were CS7 (8\%), CS14 (PCFO166) (7\%), CS12 (PCFO159) (4\%), CS17 (3\%), and CS8 (CFA/III) (2.7\%). The ST- or LT- and ST-positive ETEC isolates expressed the CFs known to be the most prevalent (i.e., CFA/I, CFA/II, and CFA/IV), while the strains positive for LT only did not. Among children who were infected with ETEC as the single pathogen, a trend of relatively more severe disease in children infected with ST-positive (P < 0.001) or LT- and ST-positive (P < 0.001) ETEC isolates compared to the severity of the disease in children infected with LT only-positive ETEC isolates was seen. This study supports the fact that ETEC is still a major cause of childhood diarrhea in Bangladesh, especially in children up to 3 years of age, and that measures to prevent such infections are needed in developing countries.
This article was published in J Clin Microbiol
and referenced in Journal of Gastrointestinal & Digestive System