Molecular identification of Phialophora oxyspora as the cause of mycetoma in a horse.

The research discusses a case where an 18-year-old mare had an oral mass due to an infection caused by a fungal species, Phialophora oxyspora. Through molecular and histological analysis, the researchers were able to diagnose and properly treat the infection.

Objective of the Study

• The study was aimed at diagnosing the cause of an oral mass in an 18-year-old mare, specifically, identifying whether mycetomata (fungal infection) was responsible for the oral mass and if so, identifying the specific fungal species responsible for the infection.

Methodology

• The researchers started with a physical examination of the horse and used radiography to visualise any abnormalities in the oral region.
• They then conducted histological examination of the oral mass which revealed foci of abscess formation and the presence of fungal hyphae.
• When culture-based identification methods proved inconclusive, the researchers isolated the fungal DNA and sequenced parts of it. It’s important to note that DNA sequencing is a reliable method to obtain definitive identification of organisms rather than relying on physical or growth characteristics.

Results & Conclusion

• After DNA sequencing, the fungus was identified as Phialophora oxyspora with 96% homology. The researchers then proceeded with surgical excision of the mass and other treatments including the administration of phenylbutazone, sodium iodide and potassium iodide.
• One year later, the horse showed no signs of recurrence indicating the success of the treatment and the accuracy of the diagnosis.
• Therefore, the researchers concluded that Mycetomata should be a differential diagnosis for equine gingival masses. They also emphasized on the fact that accurate identification of the fungal agent is critical for the selection of optimal treatments and molecular methods may permit definitive identification when the standard phenotype-based identification criteria are inconclusive.