Molecular Characterization of Shiga Toxin Producing Escherichia coli from Raw Milk Samples

Abstract

Shiga toxin-producing E. coli (STEC) has been associated with both outbreaks and sporadic cases of human disease, ranging from uncomplicated diarrhea to haemorrhagic colitis and haemolytic uremic syndrome (HUS). The dominant STEC serotype is O157:H7, which is also most commonly involved in large number of outbreaks in the world. Keeping in view of the public health significance of STEC a small work was designed to detect the presence of STEC from milk samples that are available in Proddatur town of YSR Kadapa district, Andhra Pradesh, India. Among the 50 samples 22 isolates were found, Escherichia coli by culture method. PCR assay of the isolates revealed that out of 22 samples 3 were positive for STEC. Among the three positive samples two isolates carried stx₁ gene and one isolate carried stx₂ gene. The results indicated that the samples revealed the presence of STEC in the tested milk samples they were non O157:H7. The findings of this study revealed that there may be a danger of transmission of STEC to consumers through consumption of not properly sterilized milk and milk products.