Shiga toxin-producing Escherichia coli in humans and the food chain in Bangladesh

Shiga toxin-producing Escherichia coli (STEC) are significant pathogenic bacteria that can cause severe gastrointestinal diseases and also the hemolytic-uremic syndrome. Domestic ruminants appear to be the main reservoirs of these organisms. Although Bangladesh is an endemic zone for diarrhea caused by different enteric pathogens, no systematic study on STEC has yet been done there. We estimated the prevalence of STEC infections among diarrheal patients and the occurrences of STEC in the human food chain in Bangladesh. In addition, we evaluated methods for the isolation of STEC O157 from animal feces and foods. We found that the prevalence of STEC was low among diarrhoeal patients compared with other diarrheagenic pathogens. In contrast, there is a high prevalence of STEC including serogroup O157 in animal reservoirs and in the food chain. We concluded that the lack of STEC O157 infection among Bangladeshi population might be due to the protective immunity against these pathogens acquired by the frequent exposure to the antigens.