A novel bacterium was isolated from a freshwater hot spring, the Hale House Spring, located at Hot Springs National Park, Hot Springs, AR, USA. Cells of strain MP-01T stained Gram-negative, were rod-shaped, non-motile, strictly anaerobic and chemo-organotrophic and did not form spores. Growth occurred at 50–65 °C, with an optimum at 60 °C, at pH 6.0–8.0, with an optimum at pH 6.5–7.0, and at NaCl concentrations up to 0.5 % (w/v), with optimum growth in the absence of NaCl. Strain MP-01T was capable of fermentative growth on pyruvate or proteinaceous substrates as well as reducing Fe(III) and Mn(IV). Major fatty acids were iso-C15 : 0, iso-C16 : 0, anteiso-C17 : 0 and iso-C17 : 0. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine and the major isoprenoid quinone was MK-10. In the polyamine pattern, sym-homospermidine was the predominant compound. The DNA G+C content was 62.7 mol%. Analysis of the 16S rRNA gene sequence of the isolate indicated that strain MP-01T represents the first reported cultivated member of subdivision 23 of the Acidobacteria . It is proposed that strain MP-01T represents a novel genus and species, for which the name Thermoanaerobaculum aquaticum gen. nov., sp. nov. is proposed. The type strain of Thermoanaerobaculum aquaticum is MP-01T ( = DSM 24856T = JCM 18256T).
Since the original description of Borrelia bavariensis sp. nov. in 2009, additional samples available from humans and ticks from Europe and Mongolia, respectively, have been used to further characterize Borrelia strains belonging to this group of spirochaetes that utilize rodents as reservoir hosts. These investigations suggested the presence of related strains in Europe and Asia and confirmed their status as representing a distinct species. Furthermore, samples that were investigated by researchers from China and Japan confirm the ecological relationship of members of this proposed species with rodents and suggest that it has a wide distribution in Eurasia. Here, we use phylogenetic and genetic distance analyses to validate B. bavariensis sp. nov. as a species within the Borrelia burgdorferi sensu lato species complex. The type strain is PBiT ( = DSM 23469T = BAA-2496T).