Toxigenicity of Edwardsiella tarda isolates of fish and pig origin in experimental models.

ABSTRACT

Indian isolates of E. tarda from fish (7) and pigs (2) were examined for their enterotoxigenicity/cytotoxigenicity in rabbit ligated ileal loop (RLIL), suckling mouse, rabbit skin and Vero cell monolayers. Cell free culture filtrates (CFCF) of isolates from fish and pigs, induced blood tinged fluid accumulation in RLIL, increased vasopermeability in rabbit skin, and caused cytopathic effect in Vero cells but could not induce fluid accumulation in suckling mouse. CFCFs lost their activity on heating at 63 degrees C for 30 min or 72 degrees C for 15 sec, and also at pH < or = 4.5 or > or = 8.5. The toxic factor was released extracellularly and was nondializable.