PRESTON AGAR BASE (VEG.)

Description

Preston Agar Base (Veg) is prepared by completely replacing animal based peptones with vegetable peptones that make the medium free of BSE/TSE risks. Preston Agar Base (Veg) is the modification of medium described by Bolton and Robertson for isolation of Campylobacter species and is also recommended by APHA. Isolation of Campylobacter species on selective agar medium is made both with or without selective broth enrichment. Direct plating without enrichment is adequate for fresh faecal samples, or intestinal specimens as high numbers of the organisms may be anticipated. For food samples enrichment is required. Campylobacter species grow well in microaerobic conditions i.e. in 5% O2 (Oxygen) at 42?C in about 48 hours. Typically, on moist media, C. jejuni growth swarms, which is a useful diagnostic growth characteristic, however, this type of confluent growth makes it difficult to obtain isolated colonies. Addition of about 4 drops of glycerol to a filter paper kept within the jar/container will hamper confluent and swarming growth of Campylobacter. The antibiotic supplement renders it selective for Campylobacter species.