SPECIFIC DNA PROBES FOR THE IDENTIFICATION OF THE FISH PATHOGEN, RENIBACTERIUM-SALMONINARUM

To obtain specific DNA probes for the identification of the fish patho gen, Renibacterium salmoninarum, a discriminatory recombinant DNA libr ary was constructed using selective fragments of the bacterial genome. Three renibacterial clones, pMAM29, pMAM46 and pMAM77, containing 149 , 73, and 154 bp respectively, were isolated and characterized. The sp ecificity of the probes was confirmed by dot-blot and Southern hybridi zation analyses. Bacterial hybridization experiments revealed that pMA M29 discriminates the R. salmoninarum genome from that of other fish p athogens such as Aeromonas salmonicida, Yersinia ruckeri, Flexibacter columnaris, Lactobacillus piscicola, Vibrio ordalii, Vibrio anguillaru m and Aeromonas hydrophila. Thus, this probe may provide a new means t o diagnose bacterial kidney disease in asymptomatic fish and ova.