Actinomyces gaoshouyii sp. nov., isolated from plateau pika (Ochotona curzoniae).

Two strains (pika_113T and pika_114) of a previously undescribed Actinomyces-like bacterium were recovered from the intestinal contents of plateau pika (Ochotona curzoniae) on the Tibet-Qinghai Plateau, China. Results from biochemical characterization indicated that the two strains were phenotypically homogeneous and distinct from other previously described species of the genus Actinomyces. Based on the comparison of 16S rRNA gene sequences and genome analysis, the bacteria were determined to be a hitherto unknown subline within the genus Actinomyces, being most closely related to type strains of Actinomyces denticolens and Actinomyces timonensis with a respective 97.2 and 97.1 % similarity in their 16S rRNA gene sequences. Phylogenetic analyses confirmed that pika_113T was well separated from any other recognized species of the genus Actinomyces and within the cluster with A. denticolens and A. timonensis. The genome of strain pika_113T displayed less than 42 % relatedness in DNA-DNA hybridization with all the available genomes of existing species of the genus Actinomyces in the NCBI database. Collectively, based on the phenotypic characteristics and phylogenetic analyses results, we propose the novel isolates as representatives of Actinomyces gaoshouyii sp. nov. The type strain of Actinomyces gaoshouyii is pika_113T (=CGMCC 4.7372T=DSM 104049T), with a genomic DNA G+C content of 71 mol%.

Gut region influences the diversity and interactions of bacterial communities in pikas (Ochotona curzoniae and Ochotona daurica).

The mammalian microbial communities in the gastrointestinal tract (GIT) play important roles in host nutrition and health. However, we still lack an understanding of how these communities are organized across GIT in natural environments. Here, using 16S rRNA gene sequencing, we analyzed the bacterial community diversity, network interactions and ecosystem stability across five gut regions (mouth, stomach, small intestine, cecum and colon) emanating from two common pika species in China, including Plateau pikas (Ochotona curzoniae) inhabiting high-altitude regions, as well as Daurian pikas (O. daurica) occupying low-altitude areas. The relative abundances of dominant Bacteroidetes and Firmicutes exhibited an increasing trend from mouth to colon. Cecum and colon harbored higher bacterial diversity compared with other anatomical regions. Gut region significantly influenced the structure of bacterial communities in the GIT. Network analysis indicated that topological features showed marked variations among gut regions. Interestingly, the ecosystem stability of bacterial communities increased gradually from mouth to colon. Our results suggest that gut region influences the diversity, structure and network interactions of bacterial communities in pikas. For hindgut-fermenting herbivorous mammals, relatively higher bacterial diversity and ecosystem stability in the cecum may provide a favorable condition for the fermentation of indigestible plant polysaccharides.

A waterborne tularemia outbreak.

A waterborne tularemia outbreak is described. Forty nine cases were identified in Sansepolcro, a small Medioeval town in the province of Arezzo, Tuscany, Italy. All cases had laterocervical or sub-mandibular adenitis, and occurred within a period of three weeks during March and April 1982. The study showed association between cases and the consumption of water from an unchlorinated water system. Francisella tularensis type 1 was isolated from wild hares captured in the area.