TYPING OF CLOSTRIDIUM-PERFRINGENS STRAINS BY USE OF RANDOM AMPLIFIED POLYMORPHIC DNA (RAPD) SYSTEM IN COMPARISON WITH ZYMOTYPING

The definition of strain clonality postulates that strains showed iden tical phenotypic and genetic traits are likely to descend from a commo n ancestor even if they were isolated from different sources and locat ions. Regarding this definition, non-epidemiologically Linked strains might be clonal strains. To overcome this ambiguity, the discriminator y capability of RAPD typing was assessed firstly on eight Clostridium perfringens strains proven to be chromosomally different with one bein g the mutant of another one. Thirteen primers were tested but only two were able to differentiate seven of the eight strains. With none of t he used primers it was possible to differentiate the parental strain a nd its mutant harbouring an insertion of 180 kb. The four most discrim inant primers were retained to determine the RAPD fingerprints of a fu rther 20 previously zymotyped strains from which seventeen were unrela ted. To compare the two typing systems, the zymotype of the eight chro mosomally different strains was determined. Thus, the discriminatory i ndex was calculated on the basis of 25 unrelated C. perfringens strain s. This was 0.97 with RAPD typing and 0.99 with zymotyping. From these results we conclude that the RAPD typing which is less fastidious tha n zymotyping can be used as an epidemiological marker for C. perfringe ns. (C) 1997 Academic Press.