Plasmid profiling for strain differentiation of Clostridium perfringens from food poisoning cases and outbreaks

Introducing a short overview on methods for strain differentiation of bacteria is given. Furthermore, aspects of the occurrence and function of plasmids of C. perfringens are pointed out. Plasmid profiling was used for the characterization of 35 C. perfringens isolates involved in disease outbreaks. The usefulness of this technique was demonstrated by the retrospectice examination of food and patient isolates from ten cases and outbreaks of food poisoning 1984 to 1991. The origin of three outbreaks could be clearly confirmed due to identical plasmid profiles in all isolates. In one outbreak identical plasmid patterns were found in one food and one patient isolate. In addition two cases and one outbreak a relationship between food and patient isolates is likely if the possibility of the loss of one plasmid in one of the isolated strains is considered. The results from three outbreaks were largely inconclusive because plasmids were not present either in all or in some of the isolates.