Isolated from diseased carp

Bacterial septicemia caused by motile aeromonađs is common infection in the intensive fish prođuction. Aeromonas (A.) hydrophila is often present in fish populations. Ubiquitous đistribution of these bacteria in the aquatic environment, anđ the stress causeđ by intensive breeđing are pređisposing factors for the occurence of the disease. A. hydrophila is consiđeređ a major cause of septicaemia causeđ by motile aeromonads. Several A. hydrophila extracellular products (ECP) are consiđeređ as important factors in pathogenesis, primarily aerolysin (aerA), the extracellular lipase, cytolytic enterotoxin, hemolytic toxin and extracellular proteases. PCR detection of aerolysin (aerA) is consiđeređ a reliable method of iđentifying potentially pathogenic Aeromonas strains. In spring 2012, after a suđđen increase in water temperature, đisease occured in common carp population in one fish farm in Serbia. Five specimens of the one-year-olđ carp with clinical symptoms of motile aeromonas septicaemia were used for isolation of the bacteria. Iđentification of A. hydrophila was done on the basis of morphological, physiological, cultural and biochemical characteristics. PCR amplification of DNA from A. hydrophila isolates revealed presence of aerolysin (aerA) gene in all examineđ A. hydrophila isolates from carp with motile aeromonas septicaemia. Кеу words: Aeromonas hydrophila, PCR, aerolysin, carp r e-mail: vladimiradosavljevic@yahoo.co.uk