<i>Aeromonas hydrophila</i> B‐haemolysin: purification and examination of its role in virulence in 0‐group channel catfish, <i>Ictalurus punctatus</i> (Rafinesque)

Abstract

Abstract. A single step procedure for purification of B‐haemolysin from Aeromonas hydrophila is described which recovered 94% of the haemolytic activity with a sixfold increase in specific activity. Toxicity of haemolysin in 0‐group channel catfish was 0–6 mg of purified protein per gram offish. Of six strains of A. hydrophila evaluated for differential toxin production and virulence in 0‐group channel catfish, three B‐haemolysin‐deficient strains were virulent while three B‐haemolysin‐producing strains were avirulent.