10.22376/ijpbs.2019.10.1.p1-12 Volume 2 Issue 4 2011 (October - December) Apart from cattle, sheep and goat are important natural reservoirs of Shigatoxigenic lessThan i greaterThan Escherichia coli lessThan /i greaterThan . Faecal contamination during dressing of carcass accounts for the presence of STEC in raw meat. A total of 201 samples (104 sheep faecal and 97 sheep farm water samples) collected from various sources were subjected to PCR analysis for the presence of Shigatoxigenic lessThan i greaterThan Escherichia coli lessThan /i greaterThan using primers specific to STEC virulent genes, shiga toxins ( lessThan i greaterThan stx lessThan /i greaterThan 1 and lessThan i greaterThan stx lessThan /i greaterThan 2) and enterohaemolysin ( lessThan i greaterThan hly lessThan /i greaterThan A) with amplification size of 614bp, 779bp and 361bp respectively. Out of 201 samples, 93 showed presence of STEC (36 faecal and 27 water samples). Of the 93 STEC positive isolates, 63 (67.74%) showed presence of lessThan i greaterThan stx lessThan /i greaterThan 1, 32 (34.4%) showed lessThan i greaterThan stx lessThan /i greaterThan 2, 47 (50.53%) showed lessThan i greaterThan hly lessThan /i greaterThan A gene and 16 (17.2%) showed both lessThan i greaterThan stx lessThan /i greaterThan 1 and lessThan i greaterThan stx lessThan /i greaterThan 2. Among 58 STEC positive isolates, 7.52% (4 faecal and 3 water samples) isolates possessed all the 3 virulent genes. Enrichment with modified Tryptic Soy Broth (mTSB) containing novobiocin gave good results compared to modified lessThan i greaterThan Escherichia coli lessThan /i greaterThan (mEC) broth with novobiocin. Ch. Bindu Kiranmayi, N. Krishnaiah, N. Subhashini And Mani Maheswari STEC, PCR, Sheep faeces, Sheep farm water, Shiga toxins, mTSB and mEC. 383-389