Why scientists are rethinking the chemical ‘arms race’ against fungi

For a long time, fungal infections have meant itchy skin, discoloured nails and sometimes hair loss.

These symptoms are collectively called dermatophytosis and are caused by a group of fungi called dermatophytes.

‘’Unfortunately, immunocompromised patients can get lesions all over their body. The itchiness and the lesions can get so severe that people even get suicidal thoughts,” said Shivaprakash Rudramurthy, professor of medical mycology at the Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh.

Global warming

Dermatophytes are molds: fungi that grow in long strands. The other common category of fungi is yeast, which are single, oval-shaped cells. Among the yeasts, Candida auris is rapidly emerging as a multidrug resistant pathogen in ICU facilities. It enters the blood stream and causes severe infections, most of which are untreatable by the available antifungals. According to Prof. Rudramurthy, those infected suffer a 30-40% mortality rate.

C. auris has become a menace only in the last two decades. The first report was in 2009 in Japan. Several other fungal species have become more pathogenic only in recent times. The cause of this rise remains unresolved but scientists and medical doctors have some ideas.

Fungi grow best in damp places below 30° C, so they can grow on our skin, especially in moist areas of the body, like armpits and the genital area. However, bloodstream infections in humans were rare because they could not survive in the body’s 37° C temperature.

“Fungal infections are common in cold-blooded animals with lower body temperatures,” Sriram Varahan, a mycologist at CSIR-Centre for Cellular and Molecular Biology, Hyderabad, said.

“But global warming puts a selective pressure on fungi such that only the more heat-tolerant ones survive. These ones can survive inside our bodies too, if they gain access to it. This is called the fungal infection — mammalian selection hypothesis.”

Clinical samples

Today, roughly 20% of infections reported in hospitals are fungal in nature — yet most hospitals in India lack the capabilities and infrastructure to identify fungal pathogens, Prof Rudramurthy said.

This prompted PGIMER to begin storing fungal pathogens some 25 years ago. Today, the institute holds a stock of 15,000 clinical fungal isolates across India and helps other medical centres and clinicians identify and culture them for study, free of cost.