A dangerous drug-resistant fungus is spreading worldwide and developing traits that make it harder to treat, scientists have warned in new research. Candida auris, an invasive yeast that primarily affects people with weakened immune systems, has now been detected in more than 60 countries, including the UK.

Fungal infections already affect an estimated 6.5 million people each year and are linked to death rates of more than 50%, even when antifungal treatment is available. Researchers warn that C. auris is of particular concern because it spreads easily in healthcare settings, is often resistant to multiple antifungal drugs, and is becoming increasingly virulent.

A scientific review, published in the journal Nature Microbiology, highlighted several features which allow the fungus to spread, including its ability to shift from a yeast-like form into different structure that aids invasion and drug resistance. Specialised proteins allow it to cling to skin.

The researchers warned: “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,” reports Manchester Evening News.

Because the fungus can survive on surfaces and medical equipment, outbreaks are often linked to devices such as catheters, feeding tubes and ventilators. It is carried on the skin and in bodily fluids, and it can cause serious infections in the bloodstream, wounds and ears, and some people may carry the fungus without showing symptoms.

The study also explained that the diagnosis of C auris is often “hampered by misidentification”, which can lead to delays in starting effective treatment.  

“Taken together, these data underscore the need to develop novel antifungal agents with broad-spectrum activity against human fungal pathogens, to improve diagnostic tests, and to develop immune- and vaccine-based adjunct modalities for the treatment of high-risk patients.”

Symptoms often resemble bacterial infections, including fever and chills, but vary depending on where the infection develops. Outside the UK, severe invasive infections are associated with ‘high mortality’, the UKHSA warned.

In England, confirmed cases remain relatively rare but are on the rise. UK Health Security Agency (UKHSA) data showed 637 cases were reported between January 2013 and December 2024, with just 26 cases in 2021, 38 in 2022, 93 in 2023, and rising to 178 in 2024.

Dr Rohini Manuel, consultant microbiologist at UKHSA, said earlier this year: “Rates of C auris in hospitals in England are very low, however they have been rising in recent years. The data covers infections and colonisations, which means that the fungus is present on the skin but is not causing illness.

“UKHSA is working with the NHS to investigate the reasons behind the increase, although factors may include a rise in the fungus globally. Hospital outbreaks in this country are rare but we are supporting a small number of Trusts in managing ongoing outbreaks of colonised patients, coordinating infection prevention and control efforts, and maintaining patient safety.”

The fungus was first discovered in 2009 in the ear canal of a patient in Japan and soon spread to many countries, including India, where it was identified as a major public health threat in 2014.

“C. auris, previously rarely detected in England, has been emerging over the last decade, particularly following the lifting of travel restrictions imposed during the COVID-19 pandemic period,” the UKHSA said.

The World Health Organisation (WHO) classified C. auris as a ‘critical priority’ pathogen in 2022 due to its rapid spread and increasing resistance to existing treatments.