Tonsilliphilus suis gen. nov., sp. nov., causing tonsil infections in pigs

Abstract

A micro-organism resembling members of the genusDermatophilus, strain W254T, which was isolated from the submandibular lymph node of a pig, and an additional 16 strains isolated from swine tonsils, were studied to establish their taxonomic status. Although all 17 strains were isolated anaerobically under an atmosphere of 100 % CO2, all of them were aerotolerant anaerobes. The micro-organisms showed at least five cellular morphologies: (i) a radially protrusive thallus, which proliferated into tuber-like cells; (ii) segmentation in both tubers and thallus followed by multilocule formation, (iii) development of coccoid forms in the locules; (iv) a change from the coccoid forms to zoospores; (v) resting cells, which were able to develop into protrusive thalli again. The micro-organisms were positive for nitrate reduction, but negative for catalase, indole production, hydrolysis of urea and gelatin liquefaction. Milk was not decomposed and none of the strains was haemolytic. A total of 16 compounds, including glucose, were utilized as sole carbon sources and seven compounds, includingl-arabinose, were not utilized. Three out of the 17 strains were subjected to further studies. The micro-organisms hadmeso-diaminopimelic acid in their peptidoglycan and galactose, glucose, madurose and a trace of mannose in their whole-cell sugar patterns. The major phospholipids were phosphatidylglycerol, diphosphatidylglycerol and phosphatidylinositol.Cellular fatty acids were C15 : 0(35.7–23.1 %), C16 : 0(5.9–2.4 %) C17 : 0(62.9–39.5 %), C17 : 1(24.4–0 %) and C18 : 0(3–1.6 %). The predominant menaquinone was MK-8 (H4). The G+C content of the DNA was 69.6–71.8 mol%. Analysis of the 16S rRNA gene sequences showed that the strains clustered with the type strains of members of the familyDermatophilaceae. Based on the polyphasic taxonomic characterization carried out, all 17 strains are considered to belong to a novel species in a new genus, for which the nameTonsilliphilus suisgen. nov., sp. nov. is proposed. The type strain of the type species is W254T( = ATCC 35846T = CCM 3774T = DSM 21880T = JCM 15727T).