TWENTY-FOURTH ANNUAL EASTERN FISH HEALTH WORKSHOP Royal Pavilion Resort, Atlantic Beach, NC MARCH 9-11, 1999 Use Of PCR For The Identification Of Aeromonas salmonicida Helen Byers, Nicholas Gudkovs, and Mark Crane AAHL Fish Diseases Laboratory, CSIRO Division of Animal Health, Private Mail Bag 24, Geelong VIC 3220 AUSTRALIA. Aeromonas salmonicida is a significant bacterial pathogen of wild and farmed fish. Detection and identification of this agent is hampered by numerous difficulties, including a lack of suitable selective media, the existence of ‘atypical’ isolates, and the occurrence of ‘covert’ infections. Molecular diagnostic methods may overcome some of these problems. To date, several PCR primer sets targeting A. salmonicida, and in one case the sub-species A. salmonicida subsp. salmonicida, have been reported, but only relatively small numbers of isolates were investigated in these studies. To further evaluate these PCR primer sets and their suitability in diagnostic tests, our laboratory collection of 308 putative exotic and enzootic A. salmonicida isolates was screened using the various PCR primer sets. The PCR primers designed by Gustafson et al. (1992) identified 93% of the A. salmonicida collection, and the primers designed by Hiney et al. (1992) identified 92% of the collection. The A. salmonicida subsp. salmonicida test devised by Miyata et al. (1996) was found to be specific for its target subspecies. Further validation of these PCR tests was undertaken in an effort to develop a reliable technique for the detection of A. salmonicida in diseased fish. The use of seeded tissue samples and experimentally infected fish in this process will be discussed. The final evaluation phase involves the use of these PCR primers under field trial conditions using naturally infected fish. Return to 24th Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page