@article{winston_rivera_cai_patterson_theriot_2021, title={Secondary bile acid ursodeoxycholic acid alters weight, the gut microbiota, and the bile acid pool in conventional mice}, volume={16}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0246161}, abstractNote={Ursodeoxycholic acid (commercially available as ursodiol) is a naturally occurring bile acid that is used to treat a variety of hepatic and gastrointestinal diseases. Ursodiol can modulate bile acid pools, which have the potential to alter the gut microbiota community structure. In turn, the gut microbial community can modulate bile acid pools, thus highlighting the interconnectedness of the gut microbiota-bile acid-host axis. Despite these interactions, it remains unclear if and how exogenously administered ursodiol shapes the gut microbial community structure and bile acid pool in conventional mice. This study aims to characterize how ursodiol alters the gastrointestinal ecosystem in conventional mice. C57BL/6J wildtype mice were given one of three doses of ursodiol (50, 150, or 450 mg/kg/day) by oral gavage for 21 days. Alterations in the gut microbiota and bile acids were examined including stool, ileal, and cecal content. Bile acids were also measured in serum. Significant weight loss was seen in mice treated with the low and high dose of ursodiol. Alterations in the microbial community structure and bile acid pool were seen in ileal and cecal content compared to pretreatment, and longitudinally in feces following the 21-day ursodiol treatment. In both ileal and cecal content, members of the Lachnospiraceae Family significantly contributed to the changes observed. This study is the first to provide a comprehensive view of how exogenously administered ursodiol shapes the healthy gastrointestinal ecosystem in conventional mice. Further studies to investigate how these changes in turn modify the host physiologic response are important.}, number={2}, journal={PLOS ONE}, author={Winston, Jenessa A. and Rivera, Alissa and Cai, Jingwei and Patterson, Andrew D. and Theriot, Casey M.}, year={2021}, month={Feb} }
 @article{thanissery_mclaren_rivera_reed_betrapally_burdette_winston_jacob_callahan_theriot_2020, title={Clostridioides difficile carriage in animals and the associated changes in the host fecal microbiota}, volume={66}, ISSN={["1095-8274"]}, DOI={10.1016/j.anaerobe.2020.102279}, abstractNote={The relationship between the gut microbiota and Clostridioides difficile, and its role in the severity of C. difficile infection in humans is an area of active research. Intestinal carriage of toxigenic and non-toxigenic C. difficile strains, with and without clinical signs, is reported in animals, however few studies have looked at the risk factors associated with C. difficile carriage and the role of the host gut microbiota. Here, we isolated and characterized C. difficile strains from different animal species (predominantly canines (dogs), felines (cats), and equines (horses)) that were brought in for tertiary care at North Carolina State University Veterinary Hospital. C. difficile strains were characterized by toxin gene profiling, fluorescent PCR ribotyping, and antimicrobial susceptibility testing. 16S rRNA gene sequencing was done on animal feces to investigate the relationship between the presence of C. difficile and the gut microbiota in different hosts. Here, we show that C. difficile was recovered from 20.9% of samples (42/201), which included 33 canines, 2 felines, and 7 equines. Over 69% (29/42) of the isolates were toxigenic and belonged to 14 different ribotypes including ones known to cause CDI in humans. The presence of C. difficile results in a shift in the fecal microbial community structure in both canines and equines. Commensal Clostridium hiranonis was negatively associated with C. difficile in canines. Further experimentation showed a clear antagonistic relationship between the two strains in vitro, suggesting that commensal Clostridia might play a role in colonization resistance against C. difficile in different hosts.}, journal={ANAEROBE}, author={Thanissery, R. and McLaren, M. R. and Rivera, A. and Reed, A. D. and Betrapally, N. S. and Burdette, T. and Winston, J. A. and Jacob, M. and Callahan, B. J. and Theriot, C. M.}, year={2020}, month={Dec} }
 @misc{winston_theriot_2020, title={Diversification of host bile acids by members of the gut microbiota}, volume={11}, ISSN={["1949-0984"]}, DOI={10.1080/19490976.2019.1674124}, abstractNote={ABSTRACT Bile acid biotransformation is a collaborative effort by the host and the gut microbiome. Host hepatocytes synthesize primary bile acids from cholesterol. Once these host-derived primary bile acids enter the gastrointestinal tract, the gut microbiota chemically modify them into secondary bile acids. Interest into the gut-bile acid-host axis is expanding in diverse fields including gastroenterology, endocrinology, oncology, and infectious disease. This review aims to 1) describe the physiologic aspects of collaborative bile acid metabolism by the host and gut microbiota; 2) to evaluate how gut microbes influence bile acid pools, and in turn how bile acid pools modulate the gut microbial community structure; 3) to compare species differences in bile acid pools; and lastly, 4) discuss the effects of ursodeoxycholic acid (UDCA) administration, a common therapeutic bile acid, on the gut microbiota-bile acid-host axis.}, number={2}, journal={GUT MICROBES}, author={Winston, Jenessa A. and Theriot, Casey M.}, year={2020}, month={Mar}, pages={158–171} }
 @article{winston_rivera_cai_thanissery_montgomery_patterson_theriot_2020, title={Ursodeoxycholic Acid (UDCA) Mitigates the Host Inflammatory Response during Clostridioides difficile Infection by Altering Gut Bile Acids}, volume={88}, ISSN={["1098-5522"]}, DOI={10.1128/IAI.00045-20}, abstractNote={Clostridioides difficile infection (CDI) is associated with increasing morbidity and mortality posing an urgent threat to public health. Recurrence of CDI after successful treatment with antibiotics is high, thus necessitating discovery of novel therapeutics against this enteric pathogen. Administration of the secondary bile acid ursodeoxycholic acid (UDCA; ursodiol) inhibits the life cycles of various strains of C. difficile in vitro, suggesting that the FDA-approved formulation of UDCA, known as ursodiol, may be able to restore colonization resistance against C. difficile in vivo. ABSTRACT Clostridioides difficile infection (CDI) is associated with increasing morbidity and mortality posing an urgent threat to public health. Recurrence of CDI after successful treatment with antibiotics is high, thus necessitating discovery of novel therapeutics against this enteric pathogen. Administration of the secondary bile acid ursodeoxycholic acid (UDCA; ursodiol) inhibits the life cycles of various strains of C. difficile in vitro, suggesting that the FDA-approved formulation of UDCA, known as ursodiol, may be able to restore colonization resistance against C. difficile in vivo. However, the mechanism(s) by which ursodiol is able to restore colonization resistance against C. difficile remains unknown. Here, we confirmed that ursodiol inhibits C. difficile R20291 spore germination and outgrowth, growth, and toxin activity in a dose-dependent manner in vitro. In a murine model of CDI, exogenous administration of ursodiol resulted in significant alterations in the bile acid metabolome with little to no changes in gut microbial community structure. Ursodiol pretreatment resulted in attenuation of CDI pathogenesis early in the course of disease, which coincided with alterations in the cecal and colonic inflammatory transcriptome, bile acid-activated receptors nuclear farnesoid X receptor (FXR) and transmembrane G-protein-coupled membrane receptor 5 (TGR5), which are able to modulate the innate immune response through signaling pathways such as NF-κB. Although ursodiol pretreatment did not result in a consistent decrease in the C. difficile life cycle in vivo, it was able to attenuate an overly robust inflammatory response that is detrimental to the host during CDI. Ursodiol remains a viable nonantibiotic treatment and/or prevention strategy against CDI. Likewise, modulation of the host innate immune response via bile acid-activated receptors FXR and TGR5 represents a new potential treatment strategy for patients with CDI.}, number={6}, journal={INFECTION AND IMMUNITY}, author={Winston, Jenessa A. and Rivera, Alissa J. and Cai, Jingwei and Thanissery, Rajani and Montgomery, Stephanie A. and Patterson, Andrew D. and Theriot, Casey M.}, year={2020}, month={May} }
 @article{thanissery_winston_theriot_2017, title={Inhibition of spore germination, growth, and toxin activity of clinically relevant C-difficile strains by gut microbiota derived secondary bile acids}, volume={45}, ISSN={["1095-8274"]}, DOI={10.1016/j.anaerobe.2017.03.004}, abstractNote={The changing epidemiology of Clostridium difficile infection over the past decades presents a significant challenge in the management of C. difficile associated diseases. The gastrointestinal tract microbiota provides colonization resistance against C. difficile, and growing evidence suggests that gut microbial derived secondary bile acids (SBAs) play a role. We hypothesized that the C. difficile life cycle; spore germination and outgrowth, growth, and toxin production, of strains that vary by age and ribotype will differ in their sensitivity to SBAs. C. difficile strains R20291 and CD196 (ribotype 027), M68 and CF5 (017), 630 (012), BI9 (001) and M120 (078) were used to define taurocholate (TCA) mediated spore germination and outgrowth, growth, and toxin activity in the absence and presence of gut microbial derived SBAs (deoxycholate, isodeoxycholate, lithocholate, isolithocholate, ursodeoxycholate, ω-muricholate, and hyodeoxycholate) found in the human and mouse large intestine. C. difficile strains varied in their rates of germination, growth kinetics, and toxin activity without the addition of SBAs. C. difficile M120, a highly divergent strain, had robust germination, growth, but significantly lower toxin activity compared to other strains. Many SBAs were able to inhibit TCA mediated spore germination and outgrowth, growth, and toxin activity in a dose dependent manner, but the level of inhibition and resistance varied across all strains and ribotypes. This study illustrates how clinically relevant C. difficile strains can have different responses when exposed to SBAs present in the gastrointestinal tract.}, journal={ANAEROBE}, author={Thanissery, Rajani and Winston, Jenessa A. and Theriot, Casey M.}, year={2017}, month={Jun}, pages={86–100} }
 @article{winston_thanissery_montgomery_theriot_2016, title={Cefoperazone-treated Mouse Model of Clinically-relevant Clostridium difficile Strain R20291}, ISSN={["1940-087X"]}, DOI={10.3791/54850}, abstractNote={Clostridium difficile is an anaerobic, gram-positive, spore-forming enteric pathogen that is associated with increasing morbidity and mortality and consequently poses an urgent threat to public health. Recurrence of a C. difficile infection (CDI) after successful treatment with antibiotics is high, occurring in 20-30% of patients, thus necessitating the discovery of novel therapeutics against this pathogen. Current animal models of CDI result in high mortality rates and thus do not approximate the chronic, insidious disease manifestations seen in humans with CDI. To evaluate therapeutics against C. difficile, a mouse model approximating human disease utilizing a clinically-relevant strain is needed. This protocol outlines the cefoperazone mouse model of CDI using a clinically-relevant and genetically-tractable strain, R20291. Techniques for clinical disease monitoring, C. difficile bacterial enumeration, toxin cytotoxicity, and histopathological changes throughout CDI in a mouse model are detailed in the protocol. Compared to other mouse models of CDI, this model is not uniformly lethal at the dose administered, allowing for the observation of a prolonged clinical course of infection concordant with the human disease. Therefore, this cefoperazone mouse model of CDI proves a valuable experimental platform to assess the effects of novel therapeutics on the amelioration of clinical disease and on the restoration of colonization resistance against C. difficile.}, number={118}, journal={JOVE-JOURNAL OF VISUALIZED EXPERIMENTS}, author={Winston, Jenessa A. and Thanissery, Rajani and Montgomery, Stephanie A. and Theriot, Casey M.}, year={2016}, month={Dec} }
 @article{winston_piperisova_neel_gookin_2016, title={Cyniclomyces guttulatus Infection in Dogs: 19 Cases (2006-2013)}, volume={52}, ISSN={["1547-3317"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84957805483&partnerID=MN8TOARS}, DOI={10.5326/jaaha-ms-6307}, abstractNote={Cyniclomyces guttulatus, a gastrointestinal yeast of rabbits, is considered an uncommon, nonpathogenic, "pass through" organism and possible opportunistic pathogen in dogs that consume rabbit feces. This retrospective study aimed to characterize the presenting complaint, clinical findings, location of organisms, and final diagnosis of dogs in which yeast morphologically consistent with C. guttulatus were identified at a veterinary teaching hospital from 2006-2013. The prevalence of C. guttulatus infection in a general population of dogs from a regional animal shelter was also determined. Nineteen dogs were retrospectively identified as diagnosed with C. guttulatus infection. Among these, 79% presented with a chief complaint and/or clinical signs consistent with gastrointestinal tract disease. The most common clinical sign was chronic diarrhea. The majority of dogs had C. guttulatus identified cytologically within samples obtained from the gastrointestinal tract; however, four dogs had C. guttulatus identified in non-gastrointestinal tract samples, including a nasal biopsy (one dog) and urine (three dogs). C. guttulatus was not identified in any of 105 shelter dogs evaluated, suggesting low prevalence of C. guttulatus in our region. These findings suggest that additional studies to determine if C. guttulatus is a potential cause or consequence of gastrointestinal illness in dogs may be warranted.}, number={1}, journal={JOURNAL OF THE AMERICAN ANIMAL HOSPITAL ASSOCIATION}, author={Winston, Jenessa Andrzejewski and Piperisova, Ida and Neel, Jennifer and Gookin, Jody L.}, year={2016}, pages={42–51} }
 @article{winston_theriot_2016, title={Impact of microbial derived secondary bile acids on colonization resistance against Clostridium difficile in the gastrointestinal tract}, volume={41}, ISSN={["1095-8274"]}, DOI={10.1016/j.anaerobe.2016.05.003}, abstractNote={Clostridium difficile is an anaerobic, Gram positive, spore-forming bacillus that is the leading cause of nosocomial gastroenteritis. Clostridium difficile infection (CDI) is associated with increasing morbidity and mortality, consequently posing an urgent threat to public health. Recurrence of CDI after successful treatment with antibiotics is high, thus necessitating discovery of novel therapeutics against this pathogen. Susceptibility to CDI is associated with alterations in the gut microbiota composition and bile acid metabolome, specifically a loss of microbial derived secondary bile acids. This review aims to summarize in vitro, ex vivo, and in vivo studies done by our group and others that demonstrate how secondary bile acids affect the different stages of the C. difficile life cycle. Understanding the dynamic interplay of C. difficile and microbial derived secondary bile acids within the gastrointestinal tract will shed light on how bile acids play a role in colonization resistance against C. difficile. Rational manipulation of secondary bile acids may prove beneficial as a treatment for patients with CDI.}, journal={ANAEROBE}, author={Winston, Jenessa A. and Theriot, Casey M.}, year={2016}, month={Oct}, pages={44–50} }