Plasmid analysis as a means of strain differentiation in Clostridium perfringens.

A total of 114 Clostridium perfringens isolates were serotyped and examined for plasmids. Fifty-two strains were from hospitalized patients with diarrhea or from hospital environments, and 62 epidemiologically unrelated isolates were obtained from food poisoning outbreaks. All strains were screened for bacteriocin production against a common indicator strain of C. perfringens. In the one significant hospital outbreak of C. perfringens diarrhea, three to five plasmid types were found in strains of the predominant serotype, but no similar correlation between serotype and plasmid type was found in random isolates from a variety of sources. All of the strains associated with the diarrhea outbreak produced bacteriocins, whereas 63% of the strains from various sources produced bacteriocins. The typing data suggest a promising differentiating capability for plasmid analysis in the epidemiological study of outbreaks of food poisoning, diarrhea, or infections caused by C. perfringens.