Virulence patterns of Aeromonas eucrenophila isolated from water and infected fish

Six isolates of Aeromonas eucrenophila--2 from water and 4 from superficial skin ulcer of cat fish--were examined for haemagglutination, serum sensitivity, chitinase production and enterotoxicity, and correlation, if any, between them; only one strain showed haemagglutination and was inhibited by both D-mannose and L-fucose. All the strains showed resistance to normal human serum, but produced chitinase; one of them elaborated inducible chitinase. All these strains caused fluid accumulation only after 1-4 serial passages through rabbit ileal loops, of which one strain that elaborated inducible chitinase caused significantly more (p < 0.005) fluid accumulation. These observations indicate that there is no correlation between enterotoxicity and haemagglutination and/or serum resistance, and these properties did not change after animal passage. However, a correlation could be observed between elaboration of inducible chitinase and enterotoxin production.