Abstract
Novel Legionella-like isolates, strains Montbeliard A1(T) and Greoux 11 D13(T), isolated from two different French water sources, were studied taxonomically and phylogenetically. Morphological and biochemical characterization revealed that they were Gram-negative, aerobic, non-spore-forming bacilli with a cut-glass appearance that grew only on L-cysteine-supplemented buffered charcoal yeast extract agar. Phenotypic characterization using fatty acid and ubiquinone profiles and SDS-PAGE analysis confirmed that they were closely related, but distinct from, other species of the genus Legionella, since serotyping could not relate them to any existing serogroup. Genotypic profiles generated by randomly amplified polymorphic DNA and 16S--23S rDNA spacer region PCR analyses were unique for each of these isolates. DNA--DNA relatedness values of strains Montbeliard A1(T) and Greoux 11 D13(T) to each other and to other Legionella type strains were less than 25%. Phylogenetic affiliation of these organisms obtained by 16S rDNA sequence comparisons confirmed that they were distinct from any other known Legionella species. All the above results confirm that these strains constitute two novel species for which the names Legionella gresilensis sp. nov. (type strain Greoux 11 D13(T)=ATCC 700509(T)=CIP 106631(T)) and Legionella beliardensis sp. nov. (type strain Montbeliard A1(T)=ATCC 700512(T)=CIP 106632(T)) are proposed.