Rapid identification of Clostridium botulinum colonies by in vitro toxicity and antimicrobial susceptibility testing.

Identification of Clostridium botulinum is usually based on toxin detection of broth culture by mouse bioassay and requires 7 to 10 days to complete. Here, we describe an alternative in vitro procedure for direct identification of C. botulinum (types A and B) colonies which can be completed in 48 h. The method is based on toxigenicity of colonies demonstrable by enzyme immunoassay and resistance of C. botulinum to antimicrobial agents, sulpha-methoxazole, trimethoprim and cycloserine.