Over 200 people have been contaminated or infected with a potentially deadly strain of drug-resistant fungus during outbreaks at UK hospitals.
Some 20 separate NHS Trusts and independent hospitals detected Candida auris (C. auris) in patients, with three hospitals being forced to tackle "large" outbreaks of the pathogen that is "difficult to control".
First discovered in Japan, the family of yeasts can live on the skin and inside the body, causing complications in people with weakened immune systems.
Public Health England (PHE) said doctors at one hospital were still dealing with an outbreak of the fungus, which is resistant to a commonly prescribed fungicidal drug.
Medical staff have been issued with new guidance on detecting and dealing with the fungus, including the "intensive" disinfection of wards amid concern over the "increasing experience of the complexities" infections are posing.
Meanwhile a biosafety unit at Porton Down in Wiltshire is testing fungicidal activity of a variety of disinfectants and antiseptics.
"As at the beginning of July 2017, 20 separate NHS Trusts and independent hospitals in the United Kingdom had detected over 200 patients colonised or infected with C. auris," PHE said.
"Three hospitals have seen large nosocomial (within hospital) outbreaks that have proved difficult to control, despite intensive infection prevention and control measures, though two of these outbreaks have been declared over and one is seeing significantly fewer numbers of new acquisitions.
"Over 35 other hospitals have had patients known to be colonised with C. auris transferred to them."
PHE said there was no evidence that any of the infections had resulted in the death of a patient in the UK, although there were limitations to the data available.
Official guidance states that infections are usually minor, while serious infections are rare.
PHE said most cases detected in the UK have been of colonised patients, while around a quarter of cases have been clinical infections - including 27 patients who developed blood stream infections.
Complications arise when the fungus enters the body or blood stream during medical treatment, such as the insertion of drips of urinary catheters, or a wound.
C. auris is resistant to the first-line antifungal drug fluconazole and the species can rapidly evolve to develop resistance.
The fungus was first identified in the ear of a patient in Japan in 2009 and has since caused prolonged hospital outbreaks in India, Pakistan, Venezuela, and Colombia.
Dr Neil Wigglesworth, president of the Infection Prevention Society, said: "The spread of this fungus shows the increasing threat from resistant organisms.
"The outbreaks reinforce the importance of rigorous infection prevention and control practices to help prevent further occurrences.
"Early intervention through infection prevention will help ensure patient safety as well as protecting vital NHS resources.
"Hospital trusts in England should follow Public Health England's guidance and ensure they have plans in place to identify and manage any cases of Candida auris. Similar plans should also be implemented in Scotland, Wales and Northern Ireland."
President of the Microbiology Society, Neil Gow, who is also professor of microbiology at the Medical Research Council Centre for Medical Mycology at the University of Aberdeen, said: "Candida auris is an important emerging pathogen and in need of more research to understand how it has emerged recently around the world as a health threat - mainly to patients in special support units.
"It's worth noting in light of the recent outbreaks however that only a handful of strains are currently resistant to more than one class of antifungal treatment at the same time.
"In addition, most of the 200 UK patients from whom this organism has been isolated, have only been colonised with Candida auris - and not infected by it.
"Fewer than 30 of the 200 individuals had the yeast isolated from their bloodstream indicating disseminated infection. Also it is also reassuring that there have been no deaths in the UK from Candida auris, and our hospital staff have already learnt a lot about how to detect and protect us from this yeast."