Campylobacter blood free agar

In the laboratory, caecal samples were streaked directly onto two selective solid media: Karmali agar (Oxoid, UK) and Campylobacter blood-free agar (Oxoid) with CCDA selective supplement (Oxoid). The swabs from carcasses were placed in 5 ml of Bolton enrichment broth (Oxoid, UK) supplemented with 5% lysed horse blood and modified Bolton broth supplement. The cultures from both types of samples were incubated at 41.5 o C for 48 h under microaerobic conditions using the CampyGen kit (Oxoid). Campylobacter bacteria were isolated and identified according to the ISO 10272-1:2006 standard. Briefly, after the enrichment step, the cultures from swab samples were plated onto Karmali agar (Oxoid) and Campylobacter blood-free agar (Oxoid) with CCDA selective supplement (Oxoid) and incubated at 41.5 o C for 48 h under microaerobic conditions. The plates with caecal and carcass bacterial cultures were then examined for morphologically typical Campylobacter colonies (grayish, often with a metallic sheen, flat, and moist with a tendency to spread) and from each sample, one presumptive Campylobacter isolate was confirmed by PCR assay as previously described (Wieczorek et al. 2013) . Furthermore, the isolated strains were identified as C. jejuni or C. coli by PCR (Wieczorek and Osek 2005) .