International Journal of Systematic and Evolutionary Microbiology (2000), 50, 979–983 Printed in Great Britain Bulleidia extructa gen. nov., sp. nov., isolated from the oral cavity Julia Downes, 1 Bente Olsvik,† 2 Sarah J. Hiom, 1 David A. Spratt, 1 Sarah L. Cheeseman, 1 Ingar Olsen, 2 Andrew J. Weightman 3 and William G. Wade 1 Author for correspondence : William G. Wade. Tel : 44 207 955 2849. Fax: 44 207 955 2847. e-mail : william.wadekcl.ac.uk 1 Oral Microbiology Unit, Division of Oral Medicine, Pathology, Microbiology and Immunology, Guy’s, King’s and St Thomas’ Dental Institute, King’s College London, Guy’s Hospital, London SE1 9RT, UK 2 Institutt for oral biologi, University of Oslo, N-0316 Oslo, Norway 3 Cardiff School of Biosciences, Cardiff University, PO Box 915, Cardiff CF1 3TL, UK Five strains of anaerobic non-sporing Gram-positive bacilli isolated from advanced periodontitis (four strains) and a dentoalveolar abscess (one strain) that did not correspond to existing species were subjected to phenotypic and genetic characterization. Following 16S rDNA sequence analysis, they were found to constitute a novel branch of the low GMC Gram-positive division of the phylogenetic tree related to Erysipelothrix rhusiopathiae and Holdemania filiformis. A new genus Bulleidia, and the species Bulleidia extructa, are proposed. Growth of B. extructa in broth media was poor but was enhanced by the addition of fructose, glucose or maltose together with Tween 80. Glucose and maltose were fermented and arginine was hydrolysed. Acetate, lactate and trace amounts of succinate were the end products of glucose fermentation. The GMC content of the DNA of the type strain is 38 mol%. The type strain of Bulleidia extructa is DSM 13220 T . Keywords : Bulleidia, Eubacterium, taxonomy, phylogeny INTRODUCTION Anaerobic non-sporing Gram-positive bacilli currently assigned to the genus Eubacterium are an extremely diverse group of organisms (Moore & Holdeman Moore, 1986). A number of new species have recently been proposed (Cheeseman et al., 1996 ; Poco et al., 1996a, b ; Uematsu et al., 1993) and it is estimated that there are at least 25 un-named taxa (Wade, 1997). Phylogenetic analysis of 16S rRNA gene sequence data has placed most of these new species in either the Actinobacteria or the low GC Gram-positive division of the phylogenetic tree (Cheeseman et al., 1996; Wade et al., 1999). In this study, a group of isolates from oral infections, which could not be identified as belonging to an existing species, were studied. METHODS Bacterial strains. The strains included in the study had been provisionally identified as Eubacterium spp. (Wade et al., ................................................................................................................................................. † Sadly, Bente Olsvik passed away in December 1998. Abbreviation : PRAS, pre-reduced aerobically sterilized. The GenBank accession number for the 16S rDNA sequence of Bulleidia extructa is AF220064. 1990 ; Olsvik, 1995). Strains GF10, MK1, UM3 and W1219 T were isolated from periodontal pockets and W2274 was isolated from a dentoalveolar abscess. Erysipelothrix rhusio- pathiae NCTC 8163 T (  ATCC 19414 T ) was obtained from the NCTC and Holdemania filiformis ATCC 51649 T from the ATCC. Morphology. Strains were grown at 37 C on fastidious anaerobe agar (FAA, LabM) supplemented with 5 % horse blood under anaerobic conditions (80 % N  , 10 % H  , 10 % CO  ). Colonial morphologies were determined using a plate microscope after incubation for 7 d. Cellular morphology was recorded after Gram-staining of 3 d plate cultures. Hanging-drop preparations of 18 h cultures of peptone yeast extractglucose (PYG) broth supplemented with 05% Tween 80 were examined by phase-contrast microscopy for cellular motility. Ultrastructure. Transmission electron microscopy was used to examine the cell-wall ultrastructure. Cells were fixed in 25% glutaraldehyde in 01M Sorensen’s buffer, then centrifuged and washed in the same buffer. The cells were post-fixed in 1 % osmium tetroxide, dehydrated by a graded series of ethanol, treated with propylene oxide and em- bedded in Taab epoxy resin. Ultrathin sections were stained with uranyl acetate and lead citrate for transmission electron microscopy. Biochemical and physiological tests. Fermentation tests were performed using pre-reduced, anaerobically sterilized 01180  2000 IUMS 979