Abstract:
Shiga toxin producing Escherichia coli (STEC) have recently emerged as important food-borne
pathogens especially serotype O157:H7. Human diseases ranging from mild diarrhea to
hemorrhagic colitis, hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic
purpura can be caused by STEC, typically affecting children, elderly and immune-compromised
patients. Bangladesh is considered as an endemic area for shiga toxin producing E.coli O157:H7.
The study is conducted to isolate E.coli from bovine samples followed by genotyping
identification using PCR. For this purpose bovine feces were collected around Dhaka city to
isolate E. coli. The samples were first enriched in enrichment broth and then plated onto
MacConkey agar. A total of 61 isolates from 7 samples were presumptively selected as E. coli
from primary MacConkey plate. The isolates were subjected to detailed biochemical
characterizations using Eosin Methylene Blue (EMB) agar medium, Indole production test,
Methyl-red test, Voges-Proskauer’s test, Citrate utilization test, Triple Sugar Iron test and
fermentation test. Out of 35 samples analyzed, only 22 isolates, gave identical biochemical
properties compared to a reference E. coli strain. Culturally and biochemically positive isolates
were tested for stx1 and stx2 genes. From all these isolates, no stx1 gene was detected but 3 were
detected for stx2. Therefore, this data showed the prevalence of E. coli in Bangladesh and
demands for further study for the prevention of diseases.
