The assessment and application of a bacteriocin typing scheme for Clostridium perfringens.

A collection of 50 bacteriocins was assembled and used to type 802 isolates of Clostridium perfringens from food poisoning outbreaks and a variety of other sources. It was found that strains of the same serotype within an outbreak showed similar patterns of susceptibility to bacteriocins, and the use of "one difference' rule is proposed for interpretation of the typing patterns of epidemiologically related strains. Isolates of different serotype or of the same serotype isolated from different sources produced many variations in bacteriocin susceptibility patterns. Two computer programs were developed to assist in the interpretation of bacteriocin typing patterns. Their use showed that related and unrelated strains formed different clusters and enabled a range of the 20 most discriminatory bacteriocins to be selected. Isolates of C. perfringens from a wide range of sources were screened for their ability to produce bacteriocins. A much greater proportion of the strains from food poisoning outbreaks was bacteriocinogenic than were isolates from human and animal infections, various foods and the environment. The relevance of these findings to the occurrence of C. perfringens food poisoning is discussed.