Legionella drozanskii sp nov., Legionella rowbothamii sp nov and Legionella fallonii sp nov.: three unusual new Legionella species

Seven strains of Legionella-like amoebal pathogens (LLAPs) were characteriz ed on the basis of their cultural and staining characteristics, biochemical reactions, serology, cellular fatty acids (CFAs), isoprenoid quinone compo sition, total DNA relatedness, analysis of 16S rRNA and macrophage infectiv ity potentiator (mip) gene sequence analyses. All seven strains exhibited l imited growth on buffered charcoal yeast extract alpha (BCYE) agar, require d cysteine for growth and contained branched-chain CFAs and quinones typica l of Legionella species. The bacilli were Gram-negative and catalase-positi ve. There were varying degrees of serological cross-reactions between these LLAP strains and other previously described Legionella species. Results fr om the various tests revealed that four LLAP strains represent three unusua l new species of Legionella: Legionella drozanskii sp. nov., type strain LL AP-1(T); Legionella rowbothamii sp. nov., type strain LLAP-6(T); and Legion ella fallonii sp. nov., type strain LLAP-10(T). Three other LLAP strains, d esignated LLAP-7FL, LLAP-7NF and LLAP-9, were shown to be members of the sp ecies Legionella lytica. The deductions made from the phenetic characterist ics of these bacteria were consistent with the phylogenetic relationships i nferred from 16S rRNA and mip gene sequence analyses. This study is the fir st to speciate LLAP strains on the basis of data including quantitative DNA hybridization.