New study reveals how deadly hospital fungus resists modern drugs

Fungal infections now make up about 20% of all hospital-reported cases, yet most Indian medical facilities lack the proper infrastructure to identify these pathogens. A group of scientists has uncovered the genetic secrets behind how drug-resistant fungi survive powerful medical treatments.

The Threat of Candida auris

While traditional dermatophytes cause itchy skin, discoloured nails, and hair loss, single-celled yeast like Candida auris has become a major danger in intensive care units over the past twenty years. This pathogen enters the bloodstream and causes severe infections with a mortality rate between 30% and 40%. The first case of Candida auris was reported in Japan in 2009. Experts link the recent rise in fungal pathogenicity to global warming, explaining that higher environmental temperatures select for heat-tolerant fungi capable of surviving inside the human body.

Genetic Resistance Mechanisms

Researchers at the Jawaharlal Nehru Centre for Advanced Scientific Research in Bengaluru used clinical fungal isolates from the Postgraduate Institute of Medical Education and Research in Chandigarh to study drug resistance. They found that more than 90% of Candida auris clinical isolates resist azole-based drugs like fluconazole, while 30% resist polyenes. When exposed to fluconazole, the pathogen produces extra copies of the Erg11 gene to make more ergosterol and block the drug. For echinocandin drugs like caspofungin, researchers found mutations in the Fks1 gene that allow survival at drug doses up to 16 micrograms per milliliter.

The Eagle Effect

Researchers also observed a paradoxical survival method known as the Eagle effect, named after U.S. pathologist Harry Eagle. At exceptionally high doses of caspofungin, the fungus activates compensatory pathways and starts producing large quantities of chitin to keep its cell wall intact despite the drug. Scientists suggest clinicians need more nuanced susceptibility tests or must raise test limits for caspofungin beyond current global standards.

Context

Medical mycology is the branch of science that studies fungi capable of causing human illness, an increasingly critical field as global temperatures potentially alter the distribution and heat tolerance of microbial species. Hospitals increasingly face challenges from antimicrobial resistance, where pathogens evolve to withstand standard treatments meant to destroy them. Understanding these genetic adaptations helps researchers design better diagnostic thresholds and alternative therapeutic strategies.