Prevalence of stx1, stx2 and eaeA genes in Shiga toxin-producing Escherichia coli isolated from fish and shrimp in Bushehr

Escherichia coli produces Shiga toxin, an important pathogen in foodborne disease, and several outbreaks of food-related bacteria are known worldwide. Contamination with this organism cause watery diarrhea and dysentery. In this study, 400 samples of fish and shrimp were provided from the Boushehr province, and it has been proved the existence of E. coli by microbiological and molecular examination. For studying stx1, stx2, and eaeA genes, was used at special pair primers. Escherichia coli did not separate in packaged samples, but in unpackaged samples, E. coli was separated in 35 samples out of 200 fish samples (17.5%) and 10 samples out of 50 shrimp samples (20%). After Multiplex PCR examination in the presence of special primers at separated isolations of fish, bonds stx1, stx2, and eaeA genes were not found in any samples. It was observed bond of stx1 and eaeA genes at two isolation (20%) and a bond of stx1, stx2, and eaeA at one isolation (10%). At the same time, it has been observed that just 1 sample (33.33%) of the stx1 gene separated E. coli isolation of shrimp. In this research and past studies, it has been proved that the frequency of the stx1 gene is more than the stx2 gene. Therefore, stx1 is a dominant genetic pattern. Considering that the maximum excretion of these bacteria will be done during summer and early fall, the low frequency of these bacteria could be related to the sampling during the spring season.