Diversity among clinical isolates of Proteus penneri detected by random amplified polymorphic DNA analysis

DNA of thirteen haemolytic Proteus penneri strains of clinical origin, all producing calcium dependent haemolysin and having been derived from four Eu ropean countries was examined for plasmid profile, and outer membrane prote in profile, by random amplified polymorphic DNA-PCR (RAPD-PCR) method, and digestions with restriction endonucleases were performed. All strains conta ined two large plasmids of approximately 60 and 70 kilobase pairs (kb). In addition, four strains contained a small plasmid of about 6 kb. These four strains produced cell-bound haemolysin only. Outer membrane protein analysi s revealed subtle differences between strains. RAPD-PCR with primer I (CCGC AGCCAA) revealed 13 types, whereas primer II (AACGCGCAAC) yielded only two main types of different patterns. Results with primer I suggests a DNA sequ ence diversity within this species. The RAPD-PCR method provides a fast, ec onomical and reproducible means for the typing of P. penneri. Digestion wit h restriction endonucleases indicated a high level of DNA methylation in th is species.