Incidence of Lactococcus garvieae the cause of lactococcosis in ainbow trout farms in Chaharmahal-va Bakhtyari province anddetection of 16S rRNA gene sequencing of the isolated bacteria

Incidence of Lactococcus garveiae the causative agent of lactococcosis was studied in 32 rainbow trouts farms in Chaharmahal-va- Bakhtyari province during 2009. Totally 192 bacterial isolates were obtained from kidney tissues of the clinically affected fish on blood agar at 30ºC. After biochemical tests, a number of 68 isolates were identical as L. garvieae phenotypically. Only 36 isolates were confirmed as L. garvieae using PCR analysis. The sequencing of 16S rRNA gene of some selected isolates were performed randomly and showed that these isolates have the most relationship with the isolates from China, Japan and Australia while, less relationship was found with the Tunis isolates. These results show that incidence of lactococcosis (streptococcosis) caused by L. garvieae increased in the rainbow trout farms in Chaharmahal-va- Bakhtyari province during 2009, in comparison with previous years.