RAPID IDENTIFICATION OF RENIBACTERIUM-SALMONINARUM USING AN OLIGONUCLEOTIDE PROBE COMPLEMENTARY TO 16S RIBOSOMAL-RNA

Bacterial kidney disease in salmonid fish is caused by the slow-growing Gram-positive rod, Renibacterium salmoninarum. The partial sequence of 16S rRNA from R. salmoninarum was determined and compared with published bacterial 16S rRNA sequences. From this sequence information, a 30-bases-long oligonucleotide was designed and used as a specific probe for identification of R. salmoninarum in filter hybridization experiments. Strong, specific hybridization signals were observed for all strains of R. salmoninarum tested. Furthermore, no cross-hybridization could be seen against 22 other bacterial species, among them other salmonid fish pathogens. The detection limit for the probe in direct filter hybridization by the dot-blot technique was 2.5 × 104 bacteria. It was also possible to detect R. salmoninarum in clinical samples by direct filter hybridization. © 1993 Academic Press Limited.