TL;DR: This study suggests that the hsp60 gene is an alternative phylogenetic marker for the classification of species of the genus Bacteroides, and demonstrates that B. suis and B. tectus are a single species.
Abstract: hsp60 gene sequences were determined for members of the genus Bacteroides and sequence similarities were compared with those obtained for the 16S rRNA gene. Among the 29 Bacteroides type strains, the mean sequence similarity of the hsp60 gene (84.5 %) was significantly less than that of the 16S rRNA gene (90.7 %), indicating a high discriminatory power of the hsp60 gene. Species of the genus Bacteroides were differentiated well by hsp60 gene sequence analysis, except for Bacteroides pyogenes JCM 6294(T), Bacteroides suis JCM 6292(T) and Bacteroides tectus JCM 10003(T). The hsp60 gene sequence analysis and the levels of DNA-DNA relatedness observed demonstrated that these three type strains are a single species. Consequently, B. suis and B. tectus are heterotypic synonyms of B. pyogenes. This study suggests that the hsp60 gene is an alternative phylogenetic marker for the classification of species of the genus Bacteroides.
TL;DR: The results of the present work highlight the importance of performing anaerobic cultures in the diagnostic investigation of cases of suppurative otitis and meningoencephalitis in macropods.
Abstract: A 6-year-old female Parma wallaby (Macropus parma) at a zoo in California developed acute ataxia and left-sided circling. Despite intensive care, clinical signs progressed to incoordination and prostration, and the animal was euthanized. At necropsy, the left tympanic cavity was filled with homogeneous suppurative exudate that extended into the cranium expanding the meninges and neuroparenchyma in the lateral and ventral aspect of the caudal ipsilateral brainstem and medulla oblongata. Microscopically, the brainstem showed regional severe suppurative meningoencephalitis with large numbers of neutrophils, fewer macrophages, and lymphocytes admixed with fibrin, necrotic cellular debris, hemorrhage, and mineralization, with numerous intralesional Gram-negative bacilli. Bacteroides spp. and Porphyromonas spp. were isolated on anaerobic culture from the meninges, and the bacteria were further characterized by partial 16S ribosomal RNA gene sequencing as Bacteroides tectus and Porphyromonas gulae. Bacterial aerobic culture from the meninges yielded very low numbers of mixed flora and Proteus spp., which were considered contaminants. Culture of Mycoplasma spp. from middle ear and meninges was negative. Additionally, Toxoplasma gondii cysts were detected by immunohistochemistry in the heart and brain, and anti-Toxoplasma antibodies were detected in serum. The genera Bacteroides and Porphyromonas have been associated with oral disease in marsupials; but not with otitis and meningoencephalitis. The results of the present work highlight the importance of performing anaerobic cultures in the diagnostic investigation of cases of suppurative otitis and meningoencephalitis in macropods.