Isolation and identification of Pseudoalteromonas piscicida strain Cura-d associated with diseased damselfish (Pomacentridae) eggs

Bacteria were isolated from the diseased eggs of two damselfish (Pomacentri dae) species, Amphiprion clarkii and Amblyglyphidodon curacao. Healthy A. c larkii eggs were infected separately with four bacterial isolates from the diseased eggs, as well as with Vibrio parahaemolyticus and Listonella angui llarum. Amphiprion clarkii eggs exposed to Cura-d, an isolate from diseased A. curacao eggs, showed increased mortality compared to uninfected control eggs. The A. curacao eggs were infected separately with the same two isola tes from diseased A. curacao eggs, and similarly, eggs exposed to isolate C ura-d also showed increased mortality compared to uninfected eggs. However, the increase in mortality associated with exposure to isolate Cura-d was m ost significant in A. clarkii eggs. A 16S rDNA comparative sequence analysi s identified that isolate Cura-d was most similar to Pseudoalteromonas pisc icida, a known fish pathogen. Both Cura-d and P. piscicida were found to be polarly flagellated, Gram-negative rods with an oxidative metabolism which grew on d-mannose, d-fructose, sucrose and maltose, but not on l-threonine . Based on these properties, it is proposed that Cura-d should be classifie d as P. piscicida strain Cura-d. It is concluded that the P. piscicida stra in cura-d was associated with the increased mortality observed in A. clarki i eggs.