Identification of pathogenic Escherichia coli strain from river and sewage water in Bangladesh

Abstract

The study was conducted to isolate and identify the presence of Shiga toxin producing Escherichia coli (STEC) strains in water samples of the Old Brahmaputra River and Sewage water at Mymensingh Municipality. A total of 20 water samples were collected for this experiment. Samples were cultured on EMB agar, stained and PCR was done to detect the pathogenic E. coli. The Old Brahmaputra River is used as a sink of all types of municipal sewage, agricultural wastes, domestic wastes and religious ritual wastes through unplanned sewerage to the river water body. Low quality sanitation system and open defecation are also considerable problems to deteriorate river water quality. Due to accumulation of municipal untreated wastes to river body, it is possible to contain various pathogens. After investigation and identification, fourteen isolates of E. coli was found to contain stx-1 gene with none of stx-2 gene among twenty isolates which indicate pathogenic STEC. There may present major health risk to human and animal due to STEC. Several human diseases like mild diarrhea, bloody diarrhea or even severe hemolytic-uremic syndrome (HUS) may occur for drinking of untreated river water. Domestic ruminants can act as a reservoir for STEC and play a significant role in the epidemiology of human infections.