Plasmid profile as fingerprinting of typing Pseudomonas aeruginosa

Pyocine production typing and restriction fragment length polymor¬ phism (RFLP) of plasmid DNA with BamHl (BamHl RFLP) were com¬ pared for intraspecies discrimination of 1 00 Pseudomonas aerugi¬ nosa isolâtes. Typeability of pyocine production method was 76% while that of BamHl RFLP was 100%. BamHl RFLP was highly discriminative so as to distinguish unrelated isolâtes of close lineage. However, it was not a good method to identify isolâtes of unrelated lineage because BamHl RFLP appeared to be a subject to conver¬ gent évolution. On the other hand, conventional typing methods are based on the présence of spécifie bacterial surface structures. Therefore, conventional typing methods may sometimes lead to wrong classification of isolâtes especially when applied alone. A combination of typing methods decreased the reproducibility of the typing results. Combined use of pyocine production and BamHl RFLP proved to be a very valuable tool for epidemiological identifi¬ cation of Pseudomonas aeruginosa isolâtes.