In vitro susceptibility patterns of fungi associated with keratomycosis in horses of the northeastern United States: 68 cases (1987-2006).
Abstract: To determine in vitro susceptibility patterns of fungi associated with keratomycosis in horses in the northeastern United States and compare those patterns with results of studies from other geographic regions. Methods: Retrospective case series. Methods: 68 horses with keratomycosis. Methods: Medical records of horses with a clinical diagnosis of keratomycosis, positive results of corneal fungal cultures, and susceptibility data were reviewed from the years 1987 to 2006. Fungal identification and in vitro antifungal susceptibility test results were recorded. The percentage of susceptible isolates was compared among antifungals for all isolates together and for the most common genera individually. Results: 74 fungal isolates from 68 horses that met inclusion criteria were identified. Aspergillus, Candida, and Fusarium spp were the most frequent isolates. Grouped isolates had the highest percentage of susceptibility to nystatin (87.7%), natamycin (87.5%), and clotrimazole (80.6%). Grouped isolates had the lowest percentage of susceptibility to fluconazole (15.8%) and miconazole (27.5%). Aspergillus spp (> or = 81.0%) were most susceptible to nystatin, clotrimazole, itraconazole, and natamycin. Candida spp (100%) were most susceptible to ketaconazole, natamycin, and nystatin. Fusarium spp (100%) were only consistently susceptible to natamycin. Conclusions: On the basis of in vitro susceptibility testing, nystatin, natamycin, or clotrimazole is recommended for initial topical treatment of keratomycosis in horses from the northeastern United States. Contrary to results of studies of ocular fungal isolates of horses from other regions, Candida spp were identified more frequently and miconazole had lower in vitro efficacy in the present study.
Publication Date: 2007-10-06 PubMed ID: 17916036DOI: 10.2460/javma.231.7.1086Google Scholar: Lookup
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- Journal Article
Summary
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This research explored the susceptibility of different fungal species related to keratomycosis in horses in the northeastern United States to various antifungal treatments, with the findings suggesting that nystatin, natamycin or clotrimazole may be the most effective initial treatment options.
Research Methodology
- The study referenced a series of 68 cases involving horses diagnosed with keratomycosis between 1987 and 2006.
- The researchers examined the horses’ medical records, particularly focusing on positive results of corneal fungal cultures and susceptibility data.
- Fungal identification and in vitro antifungal susceptibility test results were recorded for analysis.
- The percentage of susceptible isolates was compared among different antifungal medications for all isolates together as well as for the most common genera separately.
Results
- There were 74 fungal isolates from 68 horses that met the criteria for inclusion in the study.
- Aspergillus, Candida, and Fusarium species were the most frequently identified fungi.
- The highest percentages of susceptibility were found with nystatin (87.7%), natamycin (87.5%), and clotrimazole (80.6%), suggesting these antifungals to be most effective against the fungi in question.
- Conversely, fluconazole (15.8%) and miconazole (27.5%) were found to be the least effective antifungals against these fungi.
- When looking at the susceptibility of different individual species, Aspergillus species displayed high susceptibility (> or = 81.0%) to nystatin, clotrimazole, itraconazole, and natamycin. Candida species were 100% susceptible to ketoconazole, natamycin, and nystatin while Fusarium species were only consistently susceptible to natamycin.
Conclusions
- Based on the in vitro susceptibility testing conducted, the researchers recommended nystatin, natamycin, or clotrimazole as initial topical treatments for keratomycosis in horses from the northeastern United States.
- The researchers noted that contrary to studies involving horses from other regions, Candida species were identified more frequently in this study and miconazole demonstrated lower in vitro efficacy.
Cite This Article
APA
Ledbetter EC, Patten VH, Scarlett JM, Vermeylen FM.
(2007).
In vitro susceptibility patterns of fungi associated with keratomycosis in horses of the northeastern United States: 68 cases (1987-2006).
J Am Vet Med Assoc, 231(7), 1086-1091.
https://doi.org/10.2460/javma.231.7.1086 Publication
Researcher Affiliations
- Department of Clinical Sciences, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA.
MeSH Terms
- Animals
- Antifungal Agents / therapeutic use
- Dose-Response Relationship, Drug
- Drug Resistance, Fungal
- Eye Infections, Fungal / drug therapy
- Eye Infections, Fungal / microbiology
- Eye Infections, Fungal / veterinary
- Female
- Fungi / drug effects
- Horse Diseases / drug therapy
- Horse Diseases / microbiology
- Horses
- Male
- Microbial Sensitivity Tests / veterinary
- New England
- Retrospective Studies
- Treatment Outcome
Citations
This article has been cited 15 times.- Mo PM, Picard J, Gummow B. The conjunctival fungal microflora of horses in a North Queensland tropical environment and their in vitro susceptibilities to antifungal agents. Vet Res Commun 2023 Sep;47(3):1641-1651.
- Foote BC, Smith JS, Bowden AC, Allbaugh RA, Sebbag L. Case Report: Successful Management of Refractory Keratomycosis in an Alpaca Using Penetrating Keratoplasty and Combination Antifungal Therapy (Caspofungin 0.5% and Terbinafine 1%). Front Vet Sci 2021;8:644074.
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- de Moura Alonso J, Watanabe MJ, de Moraes Gimenes Bosco S, Apolonio EVP, de Vasconcelos AB, do Prado AC, Alves ALG, Rodrigues CA, Hussni CA. Treatment of mycotic rhinitis caused by aspergillus fumigatus in a quarter horse mare using topical clotrimazole and oral potassium iodide. Vet Res Commun 2024 Nov 22;49(1):28.
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