Avian and human Turicibacter isolates possess bile salt hydrolases with activity against tauro-conjugated bile acids

Authors: Maki, Joel; SHOWMAN, LUCAS - Iowa State University; Looft, Torey

Submitted to: Bacteria
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/2/2025
Publication Date: 7/18/2025
Citation: Maki, J.J., Showman, L., Looft, T.P. 2025. Avian and human Turicibacter isolates possess bile salt hydrolases with activity against tauro-conjugated bile acids. Bacteria. 4(3). Article 35. https://doi.org/10.3390/bacteria4030035.
DOI: https://doi.org/10.3390/bacteria4030035

Interpretive Summary: Maintenance of productive and healthy animals within the livestock industry is critical for feeding a growing population. Understanding the genomic variability of bacterial species in the intestinal tract of different livestock species, and the interactions these bacteria have with host-produced compounds, can support animal production and health. Bile acids are responsible for digestion and nutrient absorption but can act as a stressor for bacteria in the gut, leading some bacteria to modifying these bile acids, impacting animal health. In this study, we compared the genetic sequence of several strains of Turicibacter, a bacterium that is found in the gut of different livestock species and humans, and tested their ability to modify bile acids. Turicibacter isolates from the same host species (chickens) were more similar genetically than strains from humans and swine. Additionally, Turicibacter isolates from chickens were able to modify the bile acids commonly found in chickens, while a Turicibacter isolate from pigs was unable to modify chicken-associated bile acids. These results suggest the bile acid-modifying bacteria Turicibacter possess host specific genetic features and bile acid modification capabilities. Studies like this improve our understanding of bacteria in the intestinal tract of livestock that can have important implications for overall animal health.

Technical Abstract: The genus Turicibacter is a common inhabitant of the small intestine of numerous animal species, including chickens. However, little is known about the phenotypic and genetic diversity of the genus. Within the chicken small intestine, bile and its primary components, bile acids, are involved in nutrient absorption and modulating microbial community structure. Here, we compare T. sanguinis MOL361 (type strain of the genus), with three strains of the recently described species T. bilis, two from chicken and one from swine. Multiple bile salt hydrolase (BSH) genes, responsible for modification of host-derived bile acids, were identified in each strain and were compared to other Turicibacter BSH with known activities. The bile acid deconjugation ability of individual strains were assessed using chicken bile, as well as the primary bile acids taurochenodeoxycholic acid and taurocholic acid. Both chicken isolates, T. bilis MMM721 and T. bilis ISU324, as well as T. sanguinis MOL361, significantly reduced the concentrations of the tauro-conjugated bile acids. Overall, this work identifies the context-dependent nature of Turicibacter BSH activity.