Biology subjects

Sponseller, B.

Publications and source records attributed to Sponseller, B..

5 recordsLinked to original sources

bioRxiv2026

Characterization of the clade 4 non-toxigenic C. difficile isolate L-NTCD03 carrying the cfr(B) gene

Clostridioides difficile infection (CDI) is a toxin-mediated gastro-intestinal disease. Yet, C. difficile is a phylogenetically diverse species that includes many non-toxigenic strains. In general, these are understudied, despite having significant potential impact for our understanding of the colonization process and as therapeutic modalities. Here, we present an in-depth characterization - including the complete genome sequence - of the non-toxigenic C. difficile strain L-NTCD03. This strain belongs to PCR ribotype 416, clade 4 and multilocus sequence type 39. It is resistant to multiple antimicrobials, but not those used for treatment of CDI. We validated the relevance of the cfr(B) gene from this strain in antimicrobial resistance to clindamycin, linezolid, retapamulin and streptogramin A. We found the L-NTCD03 strain to be non-toxic in various assays. Altogether, L-NTCD03 is a promising candidate for developing into a live biotherapeutic product.

microbiology↗

bioRxiv2024

Effect of Genotype and Age on a Defined Microbiota in Gnotobiotic SCID Piglets

Severe combined immunodeficient (SCID) individuals lack functional T and B lymphocytes, leading to a deficient adaptive immune system. SCID pigs are a unique large animal biomedical model as they possess many similarities to humans, allowing for the collection of translatable data in regenerative medicine, cancer, and other biomedical research topics. While many studies suggest early gut microbiota development is necessary for developing the intestinal barrier and immune system, these animals are often cesarian section derived, leaving them uncolonized for normal intestinal microflora. The hypothesis was that an increase in complexity of microbiota inoculum will allow for more stability in the composition of the gut microbiota of SCID piglets. This was tested across multiple litters of SCID piglets with three different defined microbiota consortium (2-strain, 6-strain, 7-strain). All piglets received their designated defined microbiota by oral gavage immediately after birth and again 24 hours later. There was no effect of SCID genotype on the composition of the gut microbiota, but there was a significant effect due to piglet age. Additionally, all three defined microbiota consortia were deemed safe to use in SCID piglets, and the 7-strain microbiota was the most stable over time. Based on these results, the 7-strain defined microbiota will be added to the SCID pig husbandry protocol, allowing for a more reproducible model.

genetics↗

bioRxiv2024

Use of equine H3N8 hemagglutinin as a broadly protective influenza vaccine immunogen

An efficacious universal influenza vaccine remains a long-sought goal for human health as current vaccines suffer from shortfalls such as mid to low efficacy and the need for yearly revisions in strains use to account for viral drift/shift. Horses undergo bi-annual vaccines for H3N8 equine influenza virus, and surveillance of sera from vaccinees demonstrated very broad reactivity and neutralization to many human seasonal influenza strains. Subsequently, vaccination of mice using the equine H3N8 Kentucky/1/91 strain of equine H3N8 vaccine induced similar broadly reactive and neutralizing serum antibodies to human seasonal strains and to high pathogenicity avian influenza strains. Challenge of mice vaccinated with equine H3N8 or recombinant hemagglutinin (HA) based on the same strain protected vaccinees from high-dose lethal virus challenges. Protection was associated with the presence of neutralizing antibodies to the HA head, esterase, and stem regions that was similar to that of antibodies generated in horses after vaccination. Vaccinated ferrets exhibited similar broadly reactive serum antibody responses that protected vaccinees from clinical signs of infection and viral-induced histopathology after challenge with influenza A/07/2009 (H1N1) pandemic virus. Taken together, these data suggest that vaccination with equine H3N8 vaccine induces broad protection against influenza without the need for non-influenza viral vectors, multiple HAs, or foreign protein scaffolds common to other universal influenza vaccine candidates.

immunology↗

bioRxiv2021

Clostridioides difficile infection increases circulating p-cresol levels and dysregulates brain dopamine metabolism: linking gut-brain axis to autism and other neurologic disorders?

Gastrointestinal illnesses are one of the most common comorbidities reported in patients with neurodevelopmental diseases, including autism spectrum disorders (ASD). Gut dysbiosis, overgrowth of C. difficile, and gut microbiota-associated alterations in central neurotransmission have been implicated in ASD, where the dopaminergic axis plays an important role in the disease pathogenesis. Human C. difficile strains produce a significant amount of the toxic metabolite p-cresol, an inhibitor of dopamine beta-hydroxylase (DBH), which catalyzes the conversion of dopamine (DA) to norepinephrine (NE). p-Cresol is known to precipitate and exacerbate autistic behavior in rodents by increasing DA levels and altering DA receptor sensitivity in brain regions relevant to ASD. Therefore, we hypothesized that C. difficile infection dysregulates dopaminergic metabolism by increasing p-cresol levels in the gut and systemic circulation, and by inhibiting brain DBH, ultimately leading to elevated DA in different brain regions. For testing this hypothesis, we induced antibiotic-associated C. difficile infection in mice and determined the gut and serum p-cresol levels, serum DBH activity, and dopamine and its metabolite levels in different brain regions relevant to ASD. The results showed that C. difficile infection causes a significant increase in striatal DA, accompanied by significantly altered levels of DA metabolites and NE in different brain regions (p < 0.05). In addition, significantly increased circulating p-cresol levels and reduced DBH activity were observed in C. difficile infected mice (p < 0.05). Therefore, the results from this study suggest a potential link between C. difficile infection and alterations in the dopaminergic axis implicated in the precipitation and aggravation of ASD.

neuroscience↗

bioRxiv2021

A model screening pipeline for bile acid converting anti-Clostridioides difficile bacteria reveals unique biotherapeutic potential of Peptacetobacter hiranonis

Clostridioides difficile is an antibiotic-resistant bacterium that causes serious, toxin-mediated enteric disease in humans and animals. Gut dysbiosis and resultant alterations in the intestinal bile acid profile play an important role in the pathogenesis of C. difficile infection (CDI). Restoration of the gut microbiota and re-establishment of bacterial bile acid metabolism using fecal microbiota transplantation (FMT) has been established as a promising strategy against this disease, although this method has several limitations. Thus, a more defined and precise microbiota-based approach using bacteria that biotransform primary bile acids into secondary bile acids could effectively overcome these limitations and control CDI. Therefore, a screening pipeline was developed to isolate bile acid converting bacteria from fecal samples. Dogs were selected as a model CDI-resistant microbiota donor for this pipeline, which yielded a novel Peptacetobacter hiranonis strain that possesses unique anti-C. difficile properties, and both bile acid deconjugation and 7- dehydroxylating activities to perform bile acid conversion. The screening pipeline included a set of in vitro tests along with a precision in vivo gut colonization and bile acid conversion test using altered Schadler flora (ASF) colonized mice. In addition, this pipeline also provided essential information on the growth requirements for screening and cultivating the candidate bacterium, its survival in a CDI predisposing environment, and potential pathogenicity. The model pipeline documented here yielded multiple bile acid converting bacteria, including a P. hiranonis isolate with unique anti-C. difficile biotherapeutic potential, which can be further tested in subsequent preclinical and human clinical trials.

microbiology↗