Study Finds Need for Better Tests to Identify Candida Auris Susceptibility

Candida auris, a pathogenic yeast, has a high mortality rate, claiming the lives of over one-third of those infected. Infections commonly arise in healthcare settings where individuals are particularly susceptible, and the rates are increasing rapidly. Determining the appropriate antifungal treatment for a C. auris infection is a critical decision in clinical practice and relies on susceptibility testing. Unfortunately, many C. auris strains have developed resistance to available antifungals, necessitating the analysis of individual samples for treatment susceptibility. However, this process is costly and time-consuming due to the lack of FDA-approved, commercially available tests for C. auris. Consequently, hospital laboratories often send samples to specialized facilities for analysis. Now, a new study has revealed that commercially available antifungal tests exhibit poor performance for many treatments.

Researchers at Indiana University (Bloomington, IN, USA) examined the suitability of tests designed for other pathogenic yeast infections in assessing C. auris susceptibility. They employed four commercially available tests for pathogenic yeasts to evaluate the susceptibility of 50 C. auris isolates to existing antifungals. The results were mixed. Two tests accurately determined the effectiveness of echinocandins, an intravenous antifungal medication commonly used to treat C. auris. However, these same tests demonstrated poor performance when assessing fluconazole, an orally administered drug belonging to the triazole group, which currently represents the sole available treatment for C. auris. Additionally, some tests inaccurately reported resistance or susceptibility to a drug, providing misleading information.

Although certain tests performed adequately for specific drugs, the study highlights the absence of a comprehensive method for determining C. auris susceptibility to antifungals. The researchers emphasize the urgent need for FDA-approved, commercially available tests to facilitate clinical decisions and enhance patient care for those infected with this potentially fatal and frequently drug-resistant pathogen. The study findings were presented at ASM Microbe 2023, the annual meeting of the American Society for Microbiology.

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