Repetitive element-polymerase chain reaction for genotyping of clinical and environmental isolates of Legionella spp.

Genotyping of Legionella strains is important for the epidemiologic survey of Legionnaires' disease infections. In this study, we investigated the potential of repetitive element-polymerase chain reaction (rep-PCR) for differentiating various isolates of Legionella spp. We used 38 Legionella pneumophila isolates (collected in clinics all over Japan between 1980 and 2007), 19 environmental Legionella anisa isolates (collected in Okinawa, Nara, Osaka, and Hyogo prefecture between 1987 and 2007), and 2 Legionella-type strains. We extracted bacterial genomic DNA and applied it to rep-PCR. PCR products were then converted into bands by agarose gel electrophoresis. The L. pneumophila serogroup (SG) 1 displayed very diverse patterns. Different bands were produced for each species of Legionella, and each species was clearly distinct. Phylogenetic analysis displayed 1 cluster of L. anisa isolates, while other Legionella spp. were present at discrete levels. Our findings show that rep-PCR is an effective, rapid, and simple technique for differentiation of L. pneumophila strains as well as Legionella spp.