Scientists in Singapore have discovered a new member of the nightmarish fungus family. In a new study published this week, the scientists detail the discovery of genetically distinct types of Candida auris in multiple patients, the sixth type to be discovered so far. The fungus is one of the most feared superbug threats because it is resistant to multiple antifungal drugs and spreads rapidly in hospitals and other infection hotspots.
C. auris was first discovered in 2009. Although it does not usually cause illness in healthy people, it can cause serious infections, especially in those with weakened immune systems. These infections are often difficult to prevent because the bacteria is resistant to some or all of the antifungal drugs available to treat it, and once established in the environment, it is difficult to completely eradicate.
While C. auris infections are still rare overall, cases in the United States and elsewhere have increased significantly in recent years, and the bacteria is steadily spreading to more parts of the world. This new study, published last month in the journal Lancet Microbe, is the latest sign that C. auris has even more up its sleeves.
Doctors at Singapore General Hospital encountered a patient carrying the C. auris strain in April 2023 as part of a routine test. In Singapore, such cases tend to develop in people who have been infected elsewhere, but the patient reported not having traveled in the past two years, which intrigued doctors. They worked with other researchers to analyze the strain’s genes and found that it didn’t exactly match any of the five known groups (clanes) of fungi that scientists had already described. The team then tested C. auris strains taken from past hospitalized patients and found two more cases that matched the genetic signature of the original case, as well as another sample that other scientists had taken from a patient in Bangladesh and uploaded to a public database.
“We report the discovery of a sixth major clade of C. auris, including three epidemiologically unrelated isolates detected in Singapore and one reported in Bangladesh,” the researchers wrote. “We propose this new clade based on extensive genomic analysis showing the clustering of these four isolates and their large genetic distance from the five known clades.”
The only saving grace of this discovery is that both hospitalized cases were treatable with conventional antifungal drugs. However, these cases appear to be unrelated to each other, which suggests that this lineage may already have begun to spread silently in Singapore, and possibly other parts of the world. It is also unclear whether and how this lineage differs from other lineages in its ability to cause human disease or large-scale outbreaks. However, given the increasing reports of outbreaks around the world, it is clear that “C. auris continues to be a threat to public health,” the researchers wrote. And more needs to be done to monitor and detect this looming fungal threat in a timely manner.
