Intergenic 16S rRNA gene (rDNA)-23S rDNA sequence length polymorphisms in members of the family Legionellaceae.

A method based on PCR amplification of the 16S rRNA gene (rDNA)-23S rDNA intergenic regions was developed for the identification of species within the family Legionellaceae. The sizes of the PCR products varied from 1,353 to 350 bp. Strains of Legionella pneumophila were characterized as having products of approximately 900 and 530 bp, and L. birminghamensis had products of 1,390, 960, and 380 bp. Of the 38 species of legionellae examined, only 7 were indistinguishable (L. erythra from L. rubrilucens, L. anisa or L. cherrii from L. tucsonensis, and L. quateirensis from L. shakespearei). Two environmental isolates were identified as L. pneumophila. Strain LLAP-3, which was a symbiont of amoebae, could not be associated with any Legionella sp. studied.