Studies of phenotypic and numerical taxonomy of Vibrio spp. isolated from oyster, Crassostrea iredalei.

摘要

Oysters are regarded as valuable commercial aquaculture product in Malaysia, which are gaining high demand from hotels. However, oysters as filter-feeder are often exposed and tend to accumulate bacteria in its tissue. Some Vibrio species namely Vibrio cholerae, V. alginolyticus and V. harveyi have been reported as the causative agents of serious human infections. Therefore, an investigation was conducted to isolate and to identify Vibrio spp. in Malaysia commercial oyster, Crassostrea iredalei. A total of 32 Vibrio spp. isolates was subjected to a bacteriological identification scheme of 32 taxonomic tests that involved with the utilization of a variety of compounds as sole carbon sources. Based on Baumann and Schubert scheme, 9 isolates of V. cholerae, 9 isolates of V. alginolyticus and 14 isolates of V. harveyi were successfully isolated and identified from raw oysters. Numerical taxonomy of these Vibrio spp. carried out using NTSYS version 2.1 shown a division of three major phena when clustered by Unweighted Pair Group Method with Arithmetic Mean (UPGMA). They were V. cholerae, V. alginolyticus and V. harveyi. Numerical taxonomy was found to be a useful tool for discriminating and grouping Vibrio species in the present study.