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Equine veterinary journal2022; 55(1); 129-141; doi: 10.1111/evj.13570

Characterisation of faecal microbiota in horses medicated with oral doxycycline hyclate.

Abstract: Antimicrobial-associated diarrhoea is a common adverse effect of antimicrobial treatment in horses and has been reported following the administration of oral doxycycline. The administration of antimicrobials has also been associated with changes in the equine intestinal microbiota diversity yet has not been explored under doxycycline treatment. Objective: To describe the dynamics of the faecal microbial diversity following a 5-day oral administration of doxycycline in healthy horses with Streptococcus zooepidemicus infected tissue chambers. Methods: Experimental prospective cohort study in a single horse group. Methods: Seven healthy adult horses with S. zooepidemicus infected tissue chambers received oral doxycycline at 10 mg/kg q 12 h for 5-days following the tissue chamber inoculation. Faeces were collected prior to the tissue chamber inoculation and until 28-days post inoculation. Faecal microbiota was characterised by high throughput sequencing of the V4 region of the 16S rRNA gene on the Illumina MiSeq sequencing platform. Bioinformatic analysis was performed with Mothur and statistical analysis were conducted on R Studio. Results: A significant decrease in alpha diversity, characterised by a decrease of richness and diversity, and a decrease in beta diversity, characterised by changes in relative abundance, occurred after initiation of and during the administration of doxycycline. A decrease in Verrucomicrobia and increase in Firmicutes:Bacteroidetes ratio occurred following the initiation of treatment, with a return to initial Firmicutes:Bacteroidetes ratio during the treatment. It took 23 days after discontinuing the treatment for the faecal microbiota to return close to the initial state. Conclusions: Lack of control population within the study. Conclusions: Transitory intestinal dysbiosis occurs under oral administration of doxycycline in horses. Unassigned: Antibiotika-assoziierte Diarrhöe ist eine häufige Nebenwirkung antimikrobieller Behandlung bei Pferden und wurde nach der Verabreichung von Doxycyclin beschrieben. Die Anwendung von Antibiotika wurde außerdem mit einer Änderung der intestinalen Diversität der Mikrobiota assoziiert, dies wurde bisher allerdings nicht für die Behandlung mit Doxycyclin untersucht. Unassigned: Beschreibung der Dynamik der fäkalen Diversität der Mikrobiota nach fünftägiger oraler Verabreichung von Doxycyclin bei gesunden, mit Streptococcus zooepidemicus infizierten Pferden. Methods: Experimentale prospektive Kohortenstudie in einer einzelnen Pferdegruppe. Methods: Sieben adulten, gesunden Pferden wurden Gewebskammern implantiert. Die Pferde erhielten Doxycyclin 10 mg/kg q 12 h oral für fünf Tage nach Gewebskammer-Inokulation mit S. zooepidemicus. Kotproben wurden vor und bis 28 Tage nach Gewebskammer-Inokulation genommen. Fäkale Mikrobiota wurde charakterisiert mithilfe Hochdurchsatzsequenzierung der V4 Region des 16S rRNA Gens auf der Illumina MiSeq Sequenzierungsplattform. Eine bioinformatische Analyse mit Mothur wurde durchgeführt und eine statistische Analysierung wurde auf R Studio ausgeführt. Unassigned: Eine signifikante Reduktion der Alphadiversität, charakterisiert durch einen Rückgang in Vielfalt und Diversität, sowie eine Reduktion der Betadiversität, charakterisiert durch Abweichungen der relativen Häufigkeit, trat nach Beginn und während der Verabreichung von Doxycyclin auf. Ein Rückgang der Verrucomicrobia trat nach Behandlungsbeginn auf, sowie ein Anstieg des Firmicutes:Bacteroidetes Verhältnisses, welches während der Behandlung zu dem ursprünglichen Firmicutes:Bacteroidetes Verhältnis zurückkehrte. Nach Absetzen der Behandlung dauerte es 23 Tage, bevor die fäkale Mikrobiota annähernd zum Ursprungszustand zurückkehrte. HAUPTEINSCHRÄNKUNGEN: Mangel einer Kontrollpopulation innerhalb der Studie SCHLUSSFOLGERUNG: Eine vorrübergehende intestinale Dysbiose tritt bei Pferden nach oraler Gabe von Doxycyclin auf.
Publication Date: 2022-03-14 PubMed ID: 35202500DOI: 10.1111/evj.13570Google Scholar: Lookup
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  • Journal Article

Summary

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This research highlights the impact of the antibiotic doxycycline on the diversity of intestinal microbiota in horses, noting a decrease in diversity during treatment and a return to near-original levels 23 days post-treatment.

Research Objectives and Methodology

  • The main purpose of the study was to analyze the changes in faecal microbial diversity in horses undergoing a 5-day oral treatment of doxycycline due to Streptococcus zooepidemicus related complications.
  • The experiment was performed on seven healthy adult horses who had S. zooepidemicus infected tissue chambers.
  • Horses received a dosage of 10 mg/kg of doxycycline every 12 hours for a duration of 5-days after the tissue chamber infection. Faecal samples were collected before inoculation and continued up to 28 days post inoculation.
  • The faecal microbiota was characterized using high throughput sequencing of the V4 region of the 16S rRNA gene with the help of the Illumina MiSeq sequencing platform.
  • Data analysis was conducted using the bioinformatics tool Mothur, with statistical analysis performed via R Studio.

Results of the Research

  • The study found a significant decrease in ‘alpha diversity’, which indicates a drop in richness and diversity. For ‘beta diversity’, which signals changes in relative abundance, a reduction was also observed after initiating the doxycycline treatment. These findings suggest that doxycycline administration affects the balance of gut microbiota in horses.
  • Besides, a decrease in Verrucomicrobia and an increase in Firmicutes:Bacteroidetes ratio was reported following the start of the treatment. However, the ratio of Firmicutes:Bacteroidetes returned to its initial stage during the course of the treatment.
  • Interestingly, it was observed that it took 23 days post therapy for faecal microbiota to return close to the original state, indicating that the impact of doxycycline takes some time to wear off.

Study Limitations and Conclusion

  • A key limitation of this study was the lack of a control population to compare and contrast results.
  • Nevertheless, the study concludes that temporary intestinal dysbiosis, a microbial imbalance inside the body, occurs when horses are administered oral doxycycline. This suggests that while the antibiotic may help in treating certain infections, it does impact the makeup of gut microbiota, potentially leading to side effects such as diarrhoea.

Cite This Article

APA
Chapuis RJJ, Becker AAMJ, Dowling PM, Weese JS. (2022). Characterisation of faecal microbiota in horses medicated with oral doxycycline hyclate. Equine Vet J, 55(1), 129-141. https://doi.org/10.1111/evj.13570

Publication

ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 55
Issue: 1
Pages: 129-141

Researcher Affiliations

Chapuis, Ronan J J
  • Clinical Sciences, Biomedical Sciences, Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis.
  • Large Animal Clinical Sciences, Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Becker, Anne A M J
  • Clinical Sciences, Biomedical Sciences, Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis.
  • Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
Dowling, Patricia M
  • Large Animal Clinical Sciences, Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Weese, J Scott
  • Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.

MeSH Terms

  • Horses / genetics
  • Animals
  • RNA, Ribosomal, 16S / genetics
  • Doxycycline / therapeutic use
  • Prospective Studies
  • Feces
  • Microbiota / genetics
  • Anti-Infective Agents

Grant Funding

  • Townsend Equine Health Research Fund of the Western College of Veterinary Medicine
  • Dr Dowling's Clinical Pharmacology Research Fund

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Citations

This article has been cited 5 times.
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