A reported Antarctic environmental microorganism isolated from the blood of sheep on the Mongolian Plateau

Herein, we report a novel Carnobacterium-like organism, CS13T, isolated from the blood of sheep with persistent diarrhea from a grassland pasturing area in Xilingol League, Inner Mongolia Municipality, China. Homology analysis indicated that CS13T belongs to the genus Carnobacterium and is 100% related to the reported environmental microorganism Carnobacterium antarticum sp. CP1 (C. CP1), which was isolated from sandy soil near Davis Station, Antarctica; the following strains are closely related: Carnobacterium mobile DSM 4848 (97%) and Carnobacterium funditum DSM 5970 (96%). Similar to those of the C. CP1, the short rod-shaped cells of CS13T are 0.4-0.8 μm wide and 1.0-1.5 μm long; exist singly, paired or catenoid; are gram positive, non-spore forming, and facultatively anaerobic; and produce hemolysin. CS13T cannot produce gas or H2S but can ferment sucrose, galactose, salicin, and esculin to produce acid. However, in contrast to C. CP1, CS13T can produce acid from cellobiose and maltose and is weakly positive for D-mannose fermentation; the growth temperatures range from 20-37°C, the pH range is 5.0-9.0, and the G+C content is 37.84% (4-36°C, pH 6.0-9.5, and 38.1% for C. CP1). Furthermore, based on gene annotation analysis, we found that CS13T has 31 more specific genes than C. CP1 (133 to 102) and that the nonredundant protein similarity to C. CP1 is only 84.2%. Based on the physiological-biochemical and genetic analysis results, we infer that the organisms isolated from the Mongolian Plateau and sandy soil in Antarctica belong to the same novel species of the genus Carnobacterium; therefore, this novel species probably has distributed globally and should not be called species antarticum.Competing Interest StatementThe authors have declared no competing interest.View Full Text