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PloS one2013; 8(6); e66640; doi: 10.1371/journal.pone.0066640

Effects of administration of live or inactivated virulent Rhodococccus equi and age on the fecal microbiome of neonatal foals.

Abstract: Rhodococcus equi is an important pathogen of foals. Enteral administration of live, virulent R. equi during early life has been documented to protect against subsequent intrabronchial challenge with R. equi, indicating that enteral mucosal immunization may be protective. Evidence exists that mucosal immune responses develop against both live and inactivated micro-organisms. The extent to which live or inactivated R. equi might alter the intestinal microbiome of foals is unknown. This is an important question because the intestinal microbiome of neonates of other species is known to change over time and to influence host development. To our knowledge, changes in the intestinal microbiome of foals during early life have not been reported. Thus, the purpose of this study was to determine whether age (during the first month of life) or administration of either live virulent R. equi (at a dose reported to protect foals against subsequent intrabronchial challenge, viz., 1×10(10) colony forming units [CFU]) or inactivated virulent R. equi (at higher doses, viz., 2×10(10) and 1×10(11) [CFU]) altered the fecal microbiome of foals. Results: Fecal swab samples from 42 healthy foals after vaccination with low-dose inactivated R. equi (n = 9), high-dose inactivated R. equi (n = 10), live R. equi (n = 6), control with cholera toxin B (CTB, n = 9), and control without CTB (n = 8) were evaluated by 454-pyrosequencing of the 16S rRNA gene and by qPCR. No impact of treatment was observed among vaccinated foals; however, marked and significant differences in microbial communities and diversity were observed between foals at 30 days of age relative to 2 days of age. Conclusions: The results suggest age-related changes in the fecal microbial population of healthy foals do occur, however, mucosal vaccination does not result in major changes of the fecal microbiome in foals.
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Publication Date: 2013-06-13 PubMed ID: 23785508PubMed Central: PMC3681940DOI: 10.1371/journal.pone.0066640Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This article investigates the impact of administering virulent Rhodococcus equi, either live or inactivated, and the age of the neonatal foals on their fecal microbiome. The study found significant age-related changes in the microbial communities and diversity in the feces of foals but observed no major alterations due to mucosal vaccination.

Introduction and Study Purpose

  • This scientific article deals with the study of the potential effect of administration of live or inactivated bacteria, specifically Rhodococcus equi, on the composition of the intestinal microbiome of neonatal foals (baby horses). Rhodococcus equi is a pathogenic bacterium known to affect foals.
  • The study aimed to fill the knowledge gap about how this bacterium, whether in inactive or live form, might change the intestinal microbiome of these young animals. The intestinal microbiome has been shown to change over time in animals and to play a significant role in the development of the host.
  • Further, the study set out to determine the effect of foals’ age on the fecal microbiome in the first month of life. This is because the intestinal microbiome of foals during early life has not been previously studied.

Methodology

  • The team completed their research by using a controlled sample of 42 healthy foals. This sample was split to apply variations of treatment, which included both doses of inactivated R. equi at different levels, live R. equi, control with cholera toxin B (CTB), and control without CTB.
  • The results were gathered by performing 454-pyrosequencing of the 16S rRNA gene and qPCR on fecal swab samples from the foals. This allowed the research team to observe any potential variations in the fecal microbiome as a result of the treatments.

Results and Conclusion

  • The observed results of the study showed no significant effects of the treatment on the fecal microbiome of the foals. That is, neither the live nor the inactivated R. equi caused any noticeable changes to the composition of the intestinal microbiome of the subjects.
  • However, the research found that there were considerable and statistically significant differences in the foals’ microbial communities and diversity at the age of 30 days compared to at 2 days. This suggests that alterations in the fecal microbiome do take place as a foal ages, even though the administration of the mucosal vaccine does not have a noticeable effect.
  • In conclusion, although mucosal vaccination did not significantly alter foals’ fecal microbiome, age did make a difference. This potentially points to the importance of studying the influence of age on the foal’s microbiome as they grow.

Cite This Article

APA
Bordin AI, Suchodolski JS, Markel ME, Weaver KB, Steiner JM, Dowd SE, Pillai S, Cohen ND. (2013). Effects of administration of live or inactivated virulent Rhodococccus equi and age on the fecal microbiome of neonatal foals. PLoS One, 8(6), e66640. https://doi.org/10.1371/journal.pone.0066640

Publication

PloS one
ISSN: 1932-6203
NlmUniqueID: 101285081
Country: United States
Language: English
Volume: 8
Issue: 6
Pages: e66640
PII: e66640

Researcher Affiliations

Bordin, Angela I
  • Equine Infectious Diseases Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America.
Suchodolski, Jan S
    Markel, Melissa E
      Weaver, Kaytee B
        Steiner, Jörg M
          Dowd, Scot E
            Pillai, Suresh
              Cohen, Noah D

                MeSH Terms

                • Age Factors
                • Animals
                • Animals, Newborn
                • Bacterial Vaccines / administration & dosage
                • Bacterial Vaccines / immunology
                • Feces / chemistry
                • Feces / microbiology
                • Horses
                • Microbiota / genetics
                • Molecular Typing
                • RNA, Ribosomal, 16S
                • Rhodococcus equi / immunology
                • Rhodococcus equi / pathogenicity
                • Sequence Analysis, DNA
                • Vaccines, Inactivated
                • Vaccines, Live, Unattenuated

                Conflict of Interest Statement

                The authors declare that they had partial support for this work through an unrestricted gift from Boehringer-Ingelheim to our laboratory and a scholarship from Fort Dodge Animal Health/Pfizer Animal Health for Dr. Angela Bordin. This industry funding does not relate to or involve any patents, products in development, marketed products, or any other private or proprietary interests. The authors do not have any consultancy agreements with these companies, and none of this work pertains to products in development or produced by these companies. This funding does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials.

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