Treponema lecithinolyticum sp nov., a small saccharolytic spirochaete withphospholipase A and C activities associated with periodontal diseases

Strong phospholipase A (PLA) and phospholipase C (PLC) activities as potent ial virulence factors are the outstanding characteristics of eight strains of small oral spirochaetes isolated from deep periodontal lesions. By quali tative dot-blot DNA-DNA hybridization and 16S rDNA sequence comparison, the se spirochaetes form a distinct phylogenetic group, with treponema maltophi lum as its closest cultivable relative. Growth of these treponemes, cells o f which contain two endoflagella, one at each pole, was autoinhibited by th e PLA-mediated production of lysolecithin unless medium OMIZ-Pat was prepar ed without lecithin. N-Acetylglucosamine was essential and D-ribose was sti mulatory far growth. All isolates were growth-inhibited when 1% foetal calf serum was added to the medium. Growth on agar plates supplemented with hum an erythrocytes produced haemolysis. In addition to PLA and PLC, the new is olates displayed strong activities of alkaline and acid phosphatases, beta- galactosidase, beta-glucuronidase, N-acetyl-beta-glucosaminidase and sialid ase, intermediate activities of C4- and C8-esterases, naphthol phosphohydro lase and alpha-fucosidase and a distinctive 30 kDa antigen detectable on We stern blots. This phenotypically and genotypically homogeneous group is pro posed as a novel species, Treponema lecithinolyticum sp, nov., with isolate OMZ 684(T) designated as the type strain. A molecular epidemiological anal ysis using a T. lecithinolyticum-specific probe showed this organism to be associated with affected sites when compared with unaffected sites of perio dontitis patients. This association was more pronounced in patients with ra pidly progressive periodontitis than in those with adult periodontitis.