Actinomyces catuli sp. nov., from dogs

Complete Genome Sequence of Actinomyces hongkongensis HKU8T Isolated from Human Blood

Members of the genus Actinomyces are strongly associated with human diseases. We present here the complete genome sequence of Actinomyces hongkongensis HKU8^T, which consists of one circular chromosome. The strain characteristically contains various genes encoding for enzymes involved in arylamidase utilization.

Actinomyces weissii sp. nov., isolated from dogs

Two Gram-positive, rod-shaped, non-spore-forming bacteria were isolated from the oral cavities of two dogs. On the basis of 16S rRNA gene sequence similarities both strains were shown to belong to the genus Actinomyces and were most closely related to Actinomyces bovis (97.3 % and 97.5 %, respectively). The polyamine profile of the two isolates and Actinomyces bovis DSM 43014T was composed of spermidine and spermine as the major components. Menaquinone MK-9 was the major compound in the quinone system of the two strains and Actinomyces bovis . The polar lipid profiles of strains 2298T and 4321 were almost identical, containing diphosphatidylglycerol as the major compound, and moderate to trace amounts of phosphatidylcholine, phosphatidylinositol, phosphatidylinositol-mannoside, phosphatidylglycerol and several unidentified lipids. A highly similar polar lipid profile was detected in Actinomyces bovis DSM 43014T supporting the affiliation of strains 2298T and 4321 to the genus Actinomyces . The typical major fatty acids were C16 : 0, C18 : 0 and C18 : 1ω9c. Fatty acids C14 : 0 and C18 : 2ω6,9c were found in minor amounts. The results of physiological and biochemical analyses revealed clear differences between both strains and the most closely related species of the genus Actinomyces . Thus, strains 2298T and 4321 represent a novel species, for which the name Actinomyces weissii sp. nov., is proposed, with strain 2298T ( = CIP 110333T = LMG 26472T = CCM 7951T = CCUG 61299T) as the type strain.

Actinomyces naturae sp. nov., the first Actinomyces sp. isolated from a non-human or animal source

Three facultatively anaerobic, Gram-positive staining, rod-shaped, non-spore forming, flagellated bacterial strains, BL-75, BL-79(T) and BL-104, were isolated from chlorinated solvent-contaminated groundwater. Phylogenetic analysis based on 16S rRNA gene sequence comparisons showed them to represent a distinct lineage within the genus Actinomyces with sequence identities in the range of <88-95.4% with previously described Actinomyces species. The strains were oxidase and catalase negative. Nitrate was not reduced. Esculin was hydrolyzed. Growth occurred in the temperature range of 20-43°C (optimum 30-37°C) and pH range 4.5-9.0 (optimum pH 6.5). Substrates supporting growth included various mono-, di-, and tri-saccharides. The end products of glucose fermentation were acetate, lactate, succinate and formate. Fermentative growth was observed in the presence of near saturation concentrations of perchloroethene (PCE) and toluene and in the presence of 1,2-dichloroethane and 1,1,2-trichloroethane at concentrations up to at least 24.4 mM and 11.2 mM, respectively. The dominant cellular fatty acids when grown in peptone/yeast extract/glucose (PYG) medium were C(18:1) ω9c, C(16:0), and C(14:0). The peptidoglycan was found to contain the amino acids alanine, glutamic acid, lysine, and ornithine at approximate molar ratios of 1.7 Ala: 2.3 Glu: 1.3 Lys: 1.0 Orn. The cell wall sugars were found to include rhamnose and mannose. The polar lipids were found to include diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phospholipid (PL), phosphoglycolipids (PGL), and glycolipids (GL). The main respiratory quinone of strain BL-79(T) was MK-9(H(4)), with minor components MK-10(H(4)) and MK-8(H(4)). The DNA mol% G+C content of the type strain is 69.8%. On the basis of phylogenetic and phenotypic characteristics, these strains could be differentiated from previously described species of the genus Actinomyces. Strains BL-75, BL-79(T) and BL-104 are designated as a novel species, for which the name Actinomyces naturae sp. nov. is proposed. This is the first Actinomyces species isolated from an environmental rather than human or animal sources. The type strain of Actinomyces naturae is BL-79(T) (= CCUG 56698(T) = NRRL B-24670(T)).

Actinomyces ruminicola sp. nov., isolated from cattle rumen

Two obligate anaerobic bacterial strains, B71Tand D471, were isolated from cattle rumen. The novel strains were Gram-positive and rod-shaped. The strains hydrolysed xylan and starch, fermented some mono-, di- and oligosaccharides and produced formic, acetic and lactic acids as end products from glucose. Growth of the isolates was observed at 20–55 °C and pH 6.5–9.0. The DNA G+C contents of strains B71Tand D471 were 68.06 and 68.26 mol%, respectively. Although the two novel strains met the genus description forActinomyces, some phenotypic characteristics, such as optimum growth temperature, requirement for O2and the end products of fermentation, distinguished them from previously described members of the genus. Phylogenetic analysis based on 16S rRNA gene sequences demonstrated that the novel strains belonged to the genusActinomyces(88.3–93.6 % sequence similarity) and formed a distinct line within the clade containingActinomyces bovis. On the basis of these results, a novel species,Actinomyces ruminicolasp. nov., is proposed. The type strain is B71T(=JCM 13352T=CGMCC 1.5030T).

Actinomyces infection in a dog with pulmonary carcinoma

Thoracic actinomycosis was diagnosed by bacterial isolation in a dog with a history of chronic productive cough, weight loss, pyrexia and a pulmonary mass lesion on radiography. Therapy with amoxycillin and clindamycin did not significantly improve the patient's condition and euthanasia was performed during exploratory thoracotomy. Histological examination of the affected lung lobes revealed the presence of peribronchiolar adenocarcinoma. Actinomycosis has been reported to co-exist with pulmonary neoplasia in humans and may mask the presence of malignancy.

Actinomyces hongkongensis sp. nov. – A Novel Actinomyces species Isolated from a Patient with Pelvic Actinomycosis

A bacterium was isolated from the pus of a patient with pelvic actinomycosis. The cells were strictly anaerobic, straight, non-sporulating, Gram-positive rods. It grows on sheep blood agar as non-haemolytic, pinpoint colonies after 24 hours of incubation at 37 degrees C in anaerobic environment. It is non-motile and does not produce catalase. 16S ribosomal RNA (rRNA) gene sequencing showed that there were 6.6% difference between the 16S rRNA gene sequence of the bacterium that of Actinomyces marimammalium (GenBank Accession no. AJ276405), a new species described in 2001, isolated from two seals and a porpoise. For these reasons a new species, Actinomyces hongkongensis sp. nov., is proposed, for which HKU8(T) is the type strain. Further studies should be performed to ascertain the potential of this bacterium to become an important cause of actinomycosis.