Used of Multiplex PCR for detection of gram-positive cocci causing farms rainbow trout (Oncorhynchus mykiss), Ilam

In the past five years, The disease that suspected streptococosis was epidemic in rainbow trout farms in Ilam, In this study, 60 rainbow trout with Clinical signs such as lethargie, erratic swimming, skin darkness and exophthalmia, were collected from rainbow trout farms in Ilam in southwest of Iran in January 2010, for detection agent of disease samples were collected from spleen, kidney and liver of fish then cultured on blood agar and incubated at 22 ºC for 24 h. Based on biochemical tests, Lactococcus garvieae was detected and isolates were confirmed as L. garvieae by using a m-PCR targeting lctO-gene, 16S rRNA and 16S- 23S rRNA Internal Transcribed Spacer region(ITS) sequencing that detect L .garvieae, Streptococcus iniae and S. dysgalactiae,. In the present study we observed a single band of 1100 bp for L. garvieae for most of isolates and concluded that the main agent of septicemia was L. garvieae. In conclusion, Multiplex PCR was definite method for rapid detection of L. garvieae in mixed infection in rainbow trout.