Comparison of two methods for detection of O157H7 in unpasteurized milk.

BACKGROUND AND OBJECTIVES

The most common serotype of enterohaemorrhagic group or Shiga-toxin-producing is O157:H7. Domestic and wild ruminants are regarded as the main natural reservoirs. O157:H7 serotype is the major cause of gastrointestinal infections in developed countries. In this study was conducted to survey on the toxigenic O157: H7 strains in milk of industrial dairy farms.

MATERIALS AND METHODS

A total number of 150 milk samples were collected from dairy industry in Khuzestan, over a period of 6 months and were evaluated by cultivation in selective media (CT-SMAC) and multiplex PCR.

RESULTS

Two isolates were identified as using biochemical tests, none of them were toxigenic O157:H7 as determined by multiplex PCR. Using direct PCR on milk samples, 45 samples contained at least one gene of the studied genes in this investigation (, ). With direct PCR, 2 milk samples were positive for toxigenic O157:H7.

CONCLUSION

O157:H7 is present in this region and so the necessity for strict compliance of health standards is recommended. This is the first study on O157: H7 milk contamination in Khuzestan province. Based on these results, direct PCR is more accurate than indirect PCR.