Distribution of hemolysin genes in Turkish Vibrio anguillarum isolates

Vibrio anguillarum, is the cause of haemorrhagic septicemia in marine and freshwater fish of various ages. Losses caused by this disease are among the most important problems in the Turkish aquaculture sector. This study characterised 51 V. anguillarum isolates obtained from sea bass, sea bream and alternative marine species cultivated in the Aegean region between 2006-2013. Isolates were identified with conventional bacteriological methods, confirmed with PCR and analysed for the presence of hemolysin genes (vah 1-5) using a multiplex PCR. Based on whole cell 0 antigen serotyping, a total of 42 isolates were serotype 01 and 9 serotype O2. The prevalence of hemolysin genes were found to be 72.54 % for vah 1, 100 % for vah 2, 86.27 % for vah 3, 82.35 % for vah 4 and 17.64 % for vah 5 respectively. Variation in serotype did not necessarily correlate with genotype. In particular, distribution of prevalence of vah genes appeared to somewhat independent of serotype, with differing numbers of hemolysin genes (vah 2,3 in 1 isolate; vah 3,4 in 1 isolate; vah 2, 4 in 3 isolates; vah 1,2,3,4 in 4 isolates) found in the 9 V. anguillarum (O 2) isolates. This data provides a useful indication of the phenotypic and genetic diversity of the V anguillarum isolates circulating in farmed marine fish reared in the Aegean region.