Prevalence of Campylobacter jejuni and Campylobacter coli isolated from raw milk samples in Mashhad

Abstract

Objective: The objective of this study was to determine the contamination rate of bulk tank milk with Campylobacter jejuni and Campylobacter coli using multiplex PCR assay. Method & Materials: In this study 200 bulk tank milk samples of Pegah pasteurization factory in Mashhad were collected randomly, during the summer months of 2007. The presence of Campylobacter genus (jejuni and coli serovars) in collected samples was assessed by performing the enrichment followed by streaking on selective media. The suspected colonies were isolated on sheep blood agar and tested for morphology, motility, gram staining, biochemical properties and hippurate hydrolysis activity. Then multiplex PCR assay (m-PCR) with three sets of primers was employed for concurrent identification of Campylobacter genus (jejuni and coli). Results & Conclusion: In m-PCR assay 8% of cultures harvest, were identified as C. jejuni and 1.5% as C. coli. In hippurate hydrolyze test number of 50 (25%) suspected colonies showed positive reaction which in m-PCR test number of 2 colonies were determined as C. coli and number of 8 colonies determined as C. jejuni. It seems that conventional method, based on hippurate hydrolysis for detection of C.jejuni, could not be a reliable test. The use of m-PCR method based on amplification from conserved genes, allows reliable detection and identification of C. jejuni and C. coli.