Detection of virulence genes (yrp1 and yrpE) in the Yersinia ruckeri by polymerase chain reaction test in Chaharmahal-Va-Bakhtiary province, Iran

Yersinia ruckeri is the etiological agent of enteric redmouth (ERM) disease, one of the important bacterial diseases in the cultured salmonids. The aim of present study was detection of virulence genes (yrpE and yrp1) in the Y.ruckeri bacterium In this study fish were evaluated in average size 10-12 Cm from six rainbow trout farms in Chaharmahal-Va-Bakhtiary province. In each farm 10 fish (totally 60) suspected to ERM were randomly selected, sampling was done from lower part of intestine and cultured on general (trypticase soy agar) and specific (Waltman-Shots) mediums. Finally, colonies that were isolated on these mediums tested by PCR method for Y.ruckeri detection. Then, in the identified strains of Y.ruckeri virulenc genes (yrp1 and yrpE) were detected by PCR test. In the all strains of Y. ruckeri two virulence genes (yrp1 and yrpE) were identified by molecular test. 24 strains out of total isolates were identified as Y.ruckeri, and among them 12 cases (50%) and 11 cases (45. 83%) had yrp1 and yrpE genes, respectively. Also, 6 samples (25%) had both genes simultaneously. Discussion and The study revealed that virulence factor yrp1 is as extracellular protease presence in Y.ruckeri strains. T his factor plays an important role in the bacterial virulence and pathogenesis of ERM disease. Data obtained in this study help to control disease especially in development of current vaccines.