Jackie Weiss, PhD speaks to MLO about how molecular diagnostics is used to identify fungal infections, including fungal infections such as Trichophyton indotineae and Candida auris.
Q. What trends are you seeing in MDx testing?
A. In recent years, we have seen the emergence of novel fungal infections, often accompanied by resistance to antifungal treatments. Molecular tests are invaluable for the detection and management of these fungal infections.
Q. Why are fungal infections an area of concern?
A. One such pathogen is Trichophyton indotineae, a dermatophyte species characterized by high transmissibility. T. indotineae is a newly emerging dermatophyte species that has developed resistance to terbinafine, a first-line antifungal, leading to a severe epidemic in South Asia. This outbreak is believed to be driven largely by the misuse and overuse of topical antifungal medications. In recent years, T. indotineae has been detected in several other countries, including the United States (U.S.).
Notably, the first sexually transmitted case of T. indotineae in the U.S. was reported in New York City this past June. Accurate detection of T. indotineae is crucial because of its resistance to antifungal agents, which can result in prolonged infection and treatment failure if not properly diagnosed.
Q. How is MDx testing being used to identify T. indotineae?
A. Identification of T. indotineae is important for epidemiological surveillance, as it helps track the spread of this emerging pathogen across different geographical regions. Molecular tests are particularly useful for identification of T. indotineae due to speed, specificity, and the ability to detect genetic markers associated with antifungal resistance.
Additionally, tests such as PCR can distinguish between Trichophyton species which may appear similar in conventional culture methods. High sensitivity of molecular tests also allows for the detection of fungal species in cases where cultures may be negative, particularly in patients who have already started antifungal treatment.
Q. Where else is MDx testing being used to address fungal infections?
A. Similarly, Candida auris has arisen as a significant public health threat in the past decade. C. auris is notable due to its rapid global emergence, high mortality rates, and frequent resistance to multiple classes of antifungals. Real-time PCR-based assays provide rapid and specific identification of C. auris, often in hours rather than days or weeks required for culture. This speed is crucial for implementing timely infection control measures and initiating appropriate treatment, as mortality is associated with delayed treatment. Identification of genetic markers associated with antifungal resistance plays an important role in the management of C. auris, as it is frequently resistant to multiple antifungal treatments.
For more on the latest MDx trends, see our most recent State of the Industry article by Kara Nadeau: MLO releases findings of 2024 SOI survey on MDx.
