Molecular typing of Listeria spp. isolated from different sources

The aim of this study was to determine the presence of Listeria spp. from different sources (beef and sheep minced meat, feces, milk and silage), and perform the genotyping of Listeria spp. strains isolated from these sources and L. monocytogenes isolates obtained from Erciyes University, Faculty of Medicine, Department of Microbiology by Rep-PCR using the DiversiLab system. A total of 350 samples were examined for the presence of Listeria spp. by conventional culture method and immunomagnetic separation method, between December 2008 and May 2009. Identification of obtained isolates was made with Microbact 12L Listeria identification test kit (Oxoid, MB1128A) and PCR was used to confirm the L. monocytogenes isolates. Listeria spp. were isolated from 22%, 10%, 48% and 16% of 50 cattle feces, 50 sheep feces, 25 beef minced meat and 25 sheep minced meat samples respectively. No Listeria spp. were obtained from the sheep and cow's milks, bulk tank milks and silage samples examined. In total, 32 Listeria spp. isolates were obtained. Of these isolates, 12 were identified as L. monocytogenes, 12 as L. innocua, 6 as L. grayi and 2 as L. welshimeri. Listeria species were divided into three different genotypic groups designated as A, B, C by Rep-PCR profiles. The same species in the groups were detected as genetically similar at a ratio of 90-99 %. High level genotypic relations were determined among the L. monocytogenes strains isolated from cattle-sheep feces, minced meat and human samples. The results reveal the importance of Listeria spp. as a foodborne pathogen, possessing zoonotic potential