Phylogeny of Legionellaceae based on small-subunit ribosomal DNA sequences and proposal of Legionella lytica comb nov for Legionella-Like amoebal pathogens

The 16S rRNA-encoding gene sequences from strains of the family Legionellaceae, Sarcobium lyticum, and Coxiella burnetii were determined. Phylogenetic relationships revealed that all Legionella spp. were members of a coherent monophyletic family. The blue-white autofluorescent species formed a defined cluster bounded by Legionella bozemanii and Legionella tucsonensis. The strains of Legionella pneumophila subsp. pneumophila and Legionella pneumophila subsp. fraseri shared 99.2% sequence identity. A legionella-like amoebal pathogen (LLAP-3) showed 99.4% sequence identity to the obligate intracellular bacterial parasite Sarcobium lyticum. A proposal is made for the transfer of Sarcobium lyticum from the genus Sarcobium to the genus Legionella as Legionella lytica comb. nov. On the basis of serology and phenetic and phylogenetic comparisons, the taxa Legionella erythra and Legionella rubrilucens may be regarded as subspecies.