New Drug-Resistant Fungal Strain Emerges as a Health Concern
A new fungus is causing alarm among health professionals due to its resistance to all major antifungal treatments. This emerging pathogen, known as Candidozyma auris (previously Candida auris), has already become a significant infection threat in hospitals worldwide.
Since it was first identified in 2009, this fungus has spread to over 60 countries across six continents, leading to serious outbreaks associated with healthcare facilities. In some cases, mortality rates have reached 30 to 50 percent.
What’s particularly concerning is how well this fungus survives in healthcare environments and its ability to spread easily among patients. Due to these factors, the World Health Organization classified C. auris as a critical-priority fungal pathogen in 2022.
The strain discussed in a recent study has raised eyebrows: laboratory tests found it resistant to all four primary classes of antifungal medications. This isolate was taken from a 28-year-old woman who developed a hospital-acquired infection following elective surgery in Nairobi, Kenya. Notably, this marks the first such case in Africa.
Genomic testing of the woman’s wound swab confirmed the presence of C. auris, belonging to a group known for high antifungal resistance. Researchers have labeled this specific strain as pan-drug-resistant (PDR), meaning it resists common antifungals like fluconazole, caspofungin, micafungin, amphotericin B, and flucytosine.
Pan-drug resistance is quite rare. This particular isolate is noted as the first of its kind in Africa and only the second documented instance globally, with the first being reported in New York in 2022.
To investigate the resistance further, researchers sequenced the entire genome of the fungus. They found several mutations known to confer antifungal resistance, including alterations in the ERG11 and CDR1 genes, connected to azole drug resistance. There was also a change in the FKS1 gene that is associated with echinocandin resistance, and a “stop-gain” mutation in FUR1, which is linked to processing flucytosine.
These genetic variations may shed light on the emergence of its resistance, though the researchers point out that the mutations seen differ from those in the previously identified New York strains. This raises questions about whether this pan-drug resistance developed independently in Kenya rather than being imported from elsewhere.
However, they cannot rule out the possibility of its origins being linked to previous exposures to antifungal drugs. The patient’s treatment history indicated she had used several antifungals during her illness, but there wasn’t enough detailed information about dosages or treatment lengths to conclude definitively whether these drugs influenced the evolution of resistance in her case.
Researchers find these findings alarming, particularly in regions where access to newer antifungal treatments is limited. They highlight the growing concern around untreatable fungal infections and are advocating for improved surveillance of fungal genomes, as well as the development of rapid diagnostic capabilities to help control the spread of highly resistant C. auris strains in healthcare settings.
Currently, this highly resistant strain of C. auris is still quite rare. Yet, it has shown an alarming ability to navigate hospital environments, gain resistance, and adapt to treatments. A fungus that can withstand virtually all standard antifungal treatments serves as a stark reminder that in the ongoing microbial arms race, even uncommon pathogens can have significant impacts.
