Evaluation of a new arcobacter enrichment medium and comparison with two media developed for enrichment of Campylobacter spp.

The productivity of an arcobacter enrichment medium (AM), newly developed by Oxoid was compared with two campylobacter enrichment media (Preston broth (Oxoid) and LabM broth), with arcobacter basal medium (ABM) as control. Twenty strains of Arcobacter and Campylobacter spp. were tested for growth, with target inocula of <4 cfu per ml of medium. Incubation was carried out aerobically for 48 h with tightly closed caps at 25°C for arcobacters and 37°C for campylobacters. After incubation the numbers of cfu in the broths were counted by surface-plating on blood agar. None of the Campylobacter spp. grew in the complete AM, and only one grew (very poorly) in the arcobacter basal medium. However, AM supported good growth of all three species of Arcobacter (A. butzleri, A. skirrowii and A. cryaerophilus) which have been associated with human and animal disease. The one strain of A. nitrofigilis tested failed to grow in any of the media except poorly in ABM. None of the Arcobacter spp. grew in Preston Broth, but nine grew in LabM broth, although productivity was poor compared to AM. None of the Campylobacter spp. grew in AM and only one grew (very poorly) in ABM.