Tel.+49 30 838 62550 Fax.+49 30 838 46029
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.