Candida auris spreads globally as scientists warn of drug-resistant 'killer fungus'

Highlights

• Drug-resistant Candida auris fungus now present in 61 countries across six continents.
• Fungal infections affect 6.5 m people annually with mortality rate exceeding 50 per cent.
• Three new drugs currently in clinical trials could offer treatment breakthrough.

A drug-resistant strain of the deadly fungus Candida auris is rapidly spreading worldwide, with scientists warning of its growing virulence and ability to evade treatment, according to a new scientific review.

The invasive yeast, which causes fatal infections particularly in people with weakened immune systems, is now present in at least 61 countries spanning six continents.

Despite antifungal therapy, the mortality rate for fungal infections remains above 50 per cent amongst the nearly 6.5 million people affected globally each year.

First discovered in 2009 in a patient's ear canal in Japan, Candida auris quickly spread internationally. India identified it as a major public health threat in 2014, establishing the country as a significant zone of concern for the infection.

Resistance and response

The review, published in Microbiology and Molecular Biology Reviews, identifies several unique characteristics that enable the fungus to spread rapidly.

The pathogen can switch between a yeast-like growth form and a filament-driven spread, accelerating its drug resistance. Cell wall proteins allow it to adhere to human skin "like glue" and colonise it effectively.

"Skin colonisation by C auris is a significant medical concern because colonised patients may facilitate inter- and intra-hospital transmission of C auris to other patients," the study states.

The fungus possesses sophisticated defence mechanisms, including "efflux pumps" on its cell membrane that expel antifungal drugs before they can be effective. It also forms slimy biofilm layers on surfaces, creating barriers that prevent drugs from penetrating. Researchers remain uncertain whether additional drug resistance mechanisms exist.

Diagnosis poses significant challenges, with the review explaining "The diagnosis of C auris infections is often hampered by misidentification, leading to delays in starting appropriate antifungal therapy."

The study emphasises the urgent need to develop novel antifungal agents with broad-spectrum activity against human fungal pathogens, improve diagnostic tests, and create immune- and vaccine-based treatment approaches for high-risk patients.

Researchers are calling for enhanced awareness campaigns and better surveillance mechanisms, particularly in resource-poor countries.

Encouragingly, three new drugs currently undergoing clinical trials could potentially become available for treating this fungal infection in the near future.