Establishment of a gnotobiotic pig model of Clostridioides difficile infection and disease

Clostridioides difficile (C. difficile) is a gram-positive, spore-forming, anaerobic bacterium known to be the most common cause of hospital-acquired and antibiotic-associated diarrhea. C. difficile infection rates are on the rise worldwide and treatment options are limited, indicating a clear need for novel therapeutics. Gnotobiotic piglets are an excellent model to reproduce the acute pseudomembranous colitis (PMC) caused by C. difficile due to their physiological similarities to humans and high susceptibility to infection. Here, we established a gnotobiotic pig model of C. difficile infection and disease using a hypervirulent strain. C. difficile-infected pigs displayed classic signs of C. difficile infection, including severe diarrhea and weight loss. Inoculated pigs had severe gross and microscopic intestinal lesions. C. difficile infection caused an increase in pro-inflammatory cytokines in samples of serum, large intestinal contents, and pleural effusion. C. difficile spores and toxins were detected in the feces of inoculated animals as tested by anaerobic culture and cytotoxicity assays. Successful establishment of this model is key for future work as therapeutics can be evaluated in an environment that accurately mimics what happens in humans. The model is especially suitable for evaluating potential prophylactics and therapeutics, including vaccines and passive immune strategies.Instituto de VirologíaFil: Nyblade, Charlotte. Virginia Polytechnic Institute and State University. Virginia-Maryland College of Veterinary Medicine. Department of Biomedical Sciences and Pathobiology; Estados UnidosFil: Parreño, Gladys Viviana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Virología e Innovaciones Tecnológicas; ArgentinaFil: Parreño, Gladys Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Parreño, Gladys Viviana. Virginia Polytechnic Institute and State University. Virginia-Maryland College of Veterinary Medicine. Department of Biomedical Sciences and Pathobiology; Estados UnidosFil: Zhou, Peng. Virginia Polytechnic Institute and State University. Virginia-Maryland College of Veterinary Medicine. Department of Biomedical Sciences and Pathobiology; Estados UnidosFil: Hensley, Casey. Virginia Polytechnic Institute and State University. Virginia-Maryland College of Veterinary Medicine. Department of Biomedical Sciences and Pathobiology; Estados UnidosFil: Oakes, Vanessa. Virginia Polytechnic Institute and State University. Virginia-Maryland College of Veterinary Medicine. Department of Biomedical Sciences and Pathobiology; Estados UnidosFil: Mahsoub, Hassan M. Virginia Polytechnic Institute and State University. Virginia-Maryland College of Veterinary Medicine. Department of Biomedical Sciences and Pathobiology; Estados UnidosFil: Mahsoub, Hassan M. Virginia Polytechnic Institute and State University. Center for Emerging, Zoonotic, and Arthropod‑Borne Pathogens; Estados UnidosFil: Kiley, Kelsey. Virginia Polytechnic Institute and State University. Virginia-Maryland College of Veterinary Medicine. Department of Biomedical Sciences and Pathobiology; Estados UnidosFil: Frazier, Maggie. Virginia Polytechnic Institute and State University. Virginia-Maryland College of Veterinary Medicine. Department of Biomedical Sciences and Pathobiology; Estados UnidosFil: Frazier, Annie. Virginia Polytechnic Institute and State University. Virginia-Maryland College of Veterinary Medicine. Department of Biomedical Sciences and Pathobiology; Estados UnidosFil: Zhang, Yongrong. University of Maryland at Baltimore. Department of Microbial Pathogenesis; Estados UnidosFil: Feng, Hanping. University of Maryland at Baltimore. Department of Microbial Pathogenesis; Estados UnidosFil: Yuan, Lijuan. Virginia Polytechnic Institute and State University. Virginia-Maryland College of Veterinary Medicine. Department of Biomedical Sciences and Pathobiology; Estados UnidosFil: Yuan, Lijuan. Virginia Polytechnic Institute and State University. Center for Emerging, Zoonotic, and Arthropod‑Borne Pathogens; Estados Unido

Thermostable, Dissolvable Buccal Film Rotavirus Vaccine Is Highly Effective in Neonatal Gnotobiotic Pig Challenge Model

Difficulties related to storage and transport of currently available live oral rotavirus vaccines can have detrimental consequences on the efficacy of the vaccines. Thus, there is a great need for thermostable vaccines that can eliminate the necessity for cold chain storage or reconstitution before administration. In this study, we developed a dissolvable oral polymeric film comprised of a live attenuated thermostable tetravalent rhesus-human reassortant rotavirus vaccine (RRV-TV) powder and antacid (CaCO3). Immunogenicity and protective efficacy of the vaccine after buccal delivery was evaluated in the gnotobiotic pig model of human rotavirus (HRV) infection and diarrhea. Two doses of the vaccine were highly immunogenic and conferred strong protection against virus shedding and diarrhea upon challenge with a high dose of a virulent G1 HRV in gnotobiotic pigs. Those pigs vaccinated with the preserved film vaccine had significantly delayed onset of diarrhea; reduced duration and area under the curve of diarrhea; delayed onset of fecal virus shedding; and reduced duration and peak of fecal virus shedding titers compared to pigs in both the placebo and the reconstituted liquid oral RRV-TV vaccine groups. Associated with the strong protection, high titers of serum virus neutralization antibodies against each of the four RRV-TV mono-reassortants and G1 HRV-specific serum IgA and IgG antibodies, as well as intestinal IgA antibodies, were induced by the preserved film vaccine. These results demonstrated the effectiveness of our thermostable buccal film rotavirus vaccine and warrant further investigation into the promise of the novel technology in addressing drawbacks of the current live oral HRV vaccines