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Veterinary research communications2023; 47(3); 1641-1651; doi: 10.1007/s11259-023-10119-9

The conjunctival fungal microflora of horses in a North Queensland tropical environment and their in vitro susceptibilities to antifungal agents.

Abstract: Fungi are ubiquitous in the environment and part of the commensal microflora on the conjunctiva of equine eyes. North Queensland, being tropical, presents an ideal environment for fungi growth. When the cornea is injured, fungi can invade the corneal stroma, resulting in keratomycosis. The objectives of this study were to determine the fungal species specific to the eyes of horses in the Townsville region; to investigate the potential risk factors associated with the presence of fungi; and to test their susceptibility to antifungals to create an empirical guide for treatment. The eyes of forty ophthalmologically normal horses from James Cook University were sampled throughout the summer months of December 2017, January 2018, and January and February 2020. Cultured fungi were identified morphologically, and their identity confirmed by comparing partial 18sRNA DNA sequences with the NCBI nucleotide database. Minimum inhibitory concentration testing of common antifungal medications was performed. Sixty-one out of eighty conjunctival samples grew fungi, and 21 different fungi genera were isolated. The most common genera were Aspergillus (18%, 26/141), Curvularia (14%,20/141), Rhodotorula (12%,17/141) and Penicillium (12%,17/141). No significant association was found between age or environmental factors and fungal culture status. Most fungi were highly susceptible to voriconazole and ketoconazole but resistant to fluconazole and amphotericin B. This adds to the body of evidence on which species of fungi are present as normal ocular microflora of horses living in tropical regions of Australia, and an avenue for treating them.
© 2023. The Author(s).
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Publication Date: 2023-04-06 PubMed ID: 37022654PubMed Central: PMC10485094DOI: 10.1007/s11259-023-10119-9Google 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.

The research article presents a study that identifies the various types of fungal species present in the eyes of horses in the tropical environment in Townsville, North Queensland, exploring possible risk factors associated with these fungi, and testing their resistance to different antifungal agents.

Research Methodology

  • The study was conducted on forty ophthalmologically normal horses from James Cook University. Their eyes were sampled during summer across December 2017, January 2018, and again in January and February 2020.
  • Conjunctival samples were grown and analyzed for the presence of fungi. The fungi were identified morphologically, confirming their identities further by comparing the component 18sRNA DNA sequences with those available in the NCBI database.
  • Additionally, the study conducted minimum inhibitory concentration testing on these fungi using common antifungal medications to determine their susceptibility to different antifungal agents.

Results and Findings

  • The study found that 61 out of 80 conjunctival samples contained fungi, and 21 different fungi genera were isolated.
  • The most frequently found genera were Aspergillus, Curvularia, Rhodotorula, and Penicillium, none of which was linked significantly with the horses’ age or environmental factors. This suggests that they are common and natural fungi present in the ocular microflora of horses.
  • When it came to antifungal testing, the majority of these fungi were highly susceptible to voriconazole and ketoconazole whereas they predominantly showed resistance to fluconazole and amphotericin B.

Conclusion

  • The research provides an understanding of the specific fungal species present in the eyes of horses living in North Queensland’s tropical regions. It shows how age or environmental factors do not have a significant impact on the presence of fungi.
  • Furthermore, the study gives an empirical guideline for treating these fungi, emphasizing the effectiveness of antifungal agents like voriconazole and ketoconazole and the resistance of the fungi to fluconazole and amphotericin B.

Cite This Article

APA
Mo PM, Picard J, Gummow B. (2023). The conjunctival fungal microflora of horses in a North Queensland tropical environment and their in vitro susceptibilities to antifungal agents. Vet Res Commun, 47(3), 1641-1651. https://doi.org/10.1007/s11259-023-10119-9

Publication

Veterinary research communications
ISSN: 1573-7446
NlmUniqueID: 8100520
Country: Switzerland
Language: English
Volume: 47
Issue: 3
Pages: 1641-1651

Researcher Affiliations

Mo, Phu Mo
  • College of Public Health, Medical and Veterinary Sciences, James Cook University, Queensland, Australia. fumo255@gmail.com.
Picard, Jacqueline
  • College of Public Health, Medical and Veterinary Sciences, James Cook University, Queensland, Australia.
Gummow, Bruce
  • College of Public Health, Medical and Veterinary Sciences, James Cook University, Queensland, Australia.
  • Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.

MeSH Terms

  • Horses
  • Animals
  • Antifungal Agents / pharmacology
  • Queensland
  • Eye Infections, Fungal / drug therapy
  • Eye Infections, Fungal / veterinary
  • Eye Infections, Fungal / microbiology
  • Amphotericin B / therapeutic use
  • Microbial Sensitivity Tests / veterinary
  • Conjunctiva / microbiology
  • Horse Diseases / drug therapy

Conflict of Interest Statement

The authors declare no conflict of interest.

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Citations

This article has been cited 1 times.
  1. Dieste-Pérez L, Holstege MMC, de Jong JE, Heuvelink AE. Azole resistance in Aspergillus isolates from animals or their direct environment (2013-2023): a systematic review. Front Vet Sci 2025;12:1507997.
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