Nachweis von Vibrio parahaemolyticus in Fischereiprodukten (Detection of Vibrio parahaemolyticus in fishery products - First experiences with a novel selective culture medium)

Within the genus of Vibrio (V) V parohoemolyticus, V cholerae and V vulnificus are the most important pathogenic vibrios for humans. The most commonly used culture medium for the identification of vibrios is the Thiosulfate-Citrate-Bilesalt-Sucrose Agar (TCBS), which tests the ability of utilising sucrose. Unfortunately, it is hardly possible to differentiate between V parahaemolyticus, V vulnificus and V mimicus, because every single of these species produces green colonies on this culture medium. Furthermore, they can lose their colour in a rather short period of time. Additional, time-consuming biochemical tests are necessary to confirm presumptive colonies. In this study, a novel chromogenic culture medium (Chromogenic Vibrio Agar CVA) for the detection of V porohaemolyticus was tested on its sensitivity and specifity compared to TCBS Agar. CVA provides a substrate for the beta-galactosidase of the target bacterium, which gives colonies a violet colour. Lacking this enzyme, other Vibrio species will not produce such colonies. The growth of 54 Vibrio spp. strains and 7 strains of non-Vibrio species were tested so far not only as a pure culture but also as a mixture of different strains. First results show that CVA not only has a greater sensitivity but also a greater specifity than TCBS Agar