Indian researchers identify drug-resistance patterns in Candida auris

Researchers studying clinical samples in India have identified genetic changes linked to Candida auris’s resistance to several antifungal medicines, highlighting difficulties in treating infections caused by the emerging pathogen. Candida auris is a yeast that can enter the bloodstream and cause severe infections, particularly in intensive-care settings. Shivaprakash Rudramurthy of the Postgraduate Institute of Medical Education and Research said infected patients face a reported mortality rate of 30% to 40%.

A recent study in Nature Communications examined clinical isolates from India using samples held at PGIMER. The institute’s collection contains about 15,000 clinical fungal isolates and supports identification and culture work for other medical centres and clinicians. Kaustuv Sanyal and research associate Aswathy Narayanan used the isolates to study how the pathogen divides and how its genome changes.

Sanyal said more than 90% of the clinical isolates examined were resistant to common azole antifungals such as fluconazole. About 30% were resistant to polyenes, another antifungal class, while most responded to echinocandins. The researchers found that some isolates exposed to fluconazole produced additional copies of the Erg11 gene, increasing production of ergosterol and reducing the drug’s effect.

They also identified mutations in the Fks1 gene that allowed the fungus to resist echinocandin treatment. Sanyal said some isolates survived caspofungin concentrations of up to 16 micrograms per millilitre, while current susceptibility testing generally goes only to 2 micrograms. The researchers suggested that testing limits should be reconsidered, although expanding tests or checking for specific mutations could increase costs.

The source material also says roughly 20% of infections reported in hospitals are fungal, while many Indian hospitals lack adequate capacity to identify fungal pathogens.