Isolation, characterization and molecular identification of a bacterial isolate of genus Cutibacterium from human stool

Emerging evidence reveals that intestinal microflora has extensive involvement in the causation, diagnosis, and treatment of many diseases. So, the present research work relates to the isolation of bacteria from faecal samples of healthy people and their phylogenetic, chemotaxonomic, morphological, physiological, and biochemical characterizations. Stool samples from a healthy person were collected. The 16S rRNA gene sequence similarity, neighbor-joining phylogenetic analysis, abundant cellular fatty acids, G+C content, respiratory quinine and predominant polar-lipids in the bacterial cells of the bacterial isolate were examined. An anaerobic bacterial isolate was isolated from the stool of a healthy person. The cells of the bacterial isolate were found to be yellowish, Gram-positive, rod-shaped and non-sporulating, and its taxonomical position was determined using a polyphasic approach. The 16S rRNA gene sequence neighbor-joining phylogenetic analysis of the bacterial isolate showed a distinct phylogenetic clade with the Cutibacterium cluster. The 16S rRNA gene sequence similarity of bacterial isolate exhibits maximum similarity with Cutibacterium avidum sp. DSM 4901T (96.5%) followed by Cutibacterium granulosumsp DSM 20700T (96.0%), Cutibacterium namnetensesp NTS31307302T (95.9%), Cutibacterium acnes sub sp. acne ATCC6919T (95.6%), Cutibacterium acnes subsp. defenden ATCC 11828T (95.7%) and Cutibacterium modestum M12 (95.5%). The abundant cellular fatty acid was iso-C15:0 followed by anteiso-C15:0 a characteristic feature of the genus Cutibacterium. The G+C content was 61.3 mol % and MK9H4 was the dominant respiratory quinine. Diphosphatidylglycerol, phosphatidylglycerol, phosphoglycolipid and phospholipid were found to be the predominant polar lipids in bacterial cells. The bacterial isolate belongs to the genus Cutibacterium based on phylogenetic, chemotaxonomic, morphological and physiological features. This isolate of Cutibacterium species has been submitted to DSMZ, Germany and NCMR, India (MCC 4755 = DSM 112163). More study is needed to understand the physio-pathogenesis and virulence of this bacterial isolate (G13) of the genus Cutibacterium species.