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Journal of veterinary internal medicine2023; 37(1); 349-360; doi: 10.1111/jvim.16612

Topography of the respiratory, oral, and guttural pouch bacterial and fungal microbiotas in horses.

Abstract: The lower respiratory tract microbiota of the horse is different in states of health and disease, but the bacterial and fungal composition of the healthy respiratory tract of the horse has not been studied in detail. Objective: The respiratory tract environment contains distinct niche microbiotas, which decrease in species richness at more distal sampling locations. Objective: Characterize the bacterial and fungal microbiotas along the upper and lower respiratory tract of the horse. Methods: Healthy Argentinian Thoroughbred horses (n = 11) from the same client-owned herd. Methods: Prospective cross-sectional study. Eleven upper and lower respiratory tract anatomical locations (bilateral nasal, bilateral deep nasal, nasopharynx, floor of mouth, oropharynx, arytenoids, proximal and distal trachea, guttural pouch) were sampled using a combination of swabs, protected specimen brushes, and saline washes. Total DNA was extracted from each sample and negative control, and the 16S rRNA gene (V4) and ITS2 region were sequenced. Community composition, alpha-diversity, and beta-diversity were compared among sampling locations. Results: Fungal species richness and diversity were highest in the nostrils. More spatial heterogeneity was found in bacterial composition than in fungal communities. The pharyngeal microbiota was most similar to the distal tracheal bacterial and fungal microbiota in healthy horses and therefore may serve as the primary source of bacteria and fungi to the lower respiratory tract. Conclusions: The pharynx is an important location that should be targeted in respiratory microbiota research in horses. Future studies that investigate whether biomarkers of respiratory disease can be reliably detected in nasopharyngeal swab samples are warranted.
Publication Date: 2023-01-06 PubMed ID: 36607177PubMed Central: PMC9889660DOI: 10.1111/jvim.16612Google Scholar: Lookup
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  • Journal Article

Summary

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This research article investigates the bacterial and fungal composition in the respiratory tract of healthy horses. The findings suggest that the pharynx may be the primary source of bacteria and fungi in the lower respiratory tract and should be a focus of future research.

Objectives and Methodology of the Study

  • The study aimed to understand the microbiotas or the communities of microorganisms that live in the upper and lower respiratory tract of healthy horses. Specifically, the objective was to characterize both bacterial and fungal microbiotas in these areas.
  • The research employed a prospective cross-sectional design on eleven healthy Argentinian Thoroughbred horses from the same owned herd.
  • Eleven upper and lower respiratory tract anatomical locations were sampled, including bilateral nasal, bilateral deep nasal, nasopharynx, floor of mouth, oropharynx, arytenoids, proximal and distal trachea, and guttural pouch.
  • Swabs, protected specimen brushes, and saline washes were used for sampling. The Total DNA was extracted from each sample and negative control, and the 16S rRNA gene (V4) and ITS2 region were sequenced.
  • The composition, alpha-diversity, and beta-diversity of the microbial communities were then compared among the sampled locations.

Key Findings of the Study

  • The richness and diversity of fungal species were found to be highest in the nostrils of the horses.
  • Different spaces within the respiratory tract showed varying compositions of bacteria, indicating diverse environments for these microorganisms within the respiratory tracts of the horses.
  • Meanwhile, the fungal communities across the different locations were less varied.
  • Both the bacterial and fungal compositions in the pharyngeal microbiota (microorganisms in the pharynx) closely resembled the compositions found in the distal tracheal microbiota, suggesting that the pharynx could be the primary source of bacteria and fungi to the lower respiratory tract in healthy horses.

Conclusions and Future Recommendations

  • The results revealed that the pharynx, as a source of the microorganisms for the lower respiratory tract, should be a key focus in future studies on respiratory microbiotas in horses.
  • The authors mentioned the need for future investigations into whether biomarkers of respiratory diseases could be a reliably detected in nasopharyngeal swab samples, given the significance of the pharynx in the microbial environment of the horse respiratory tract.

Cite This Article

APA
Bond S, McMullen C, Timsit E, Léguillette R. (2023). Topography of the respiratory, oral, and guttural pouch bacterial and fungal microbiotas in horses. J Vet Intern Med, 37(1), 349-360. https://doi.org/10.1111/jvim.16612

Publication

ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 37
Issue: 1
Pages: 349-360

Researcher Affiliations

Bond, Stephanie
  • Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada.
  • School of Veterinary Science, Faculty of Science, University of Queensland, Gatton, Australia.
McMullen, Christopher
  • Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada.
  • Feedlot Health Management Services, Inc, Okotoks, Alberta, Canada.
Timsit, Edouard
  • Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada.
  • I&D Pharma Departement, Ceva Santé Animale, Libourne, France.
Léguillette, Renaud
  • Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada.

MeSH Terms

  • Horses / genetics
  • Animals
  • Mycobiome
  • RNA, Ribosomal, 16S / genetics
  • Cross-Sectional Studies
  • Prospective Studies
  • Bacteria
  • DNA, Bacterial

Grant Funding

  • Calgary Chair in Equine Sports Medicine

Conflict of Interest Statement

Authors declare no conflict of interest.

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This article has been cited 6 times.
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