Patients infected with a deadly, drug-resistant fungus are dripping with the dangerous germ, which pours into their surroundings where it lies in wait for weeks to find a new victim. That’s according to fresh data reported from the annual meeting of the American Society for Microbiology recently in San Francisco.

The data fills in critical unknowns about how the fungus, Candida auris, actually spreads. The germ is a relatively new threat, considered an emerging pathogen by experts—and it's emerging quickly with an unusual ability to lurk and kill in healthcare settings.

It was first identified in 2009 in Japan. Studies since have tracked the globetrotting fungus backward and forward in time, from South Korea in 1996 to an outbreak in New York health facilities that began in 2013 and lasted until 2017. In all, C. auris has made an appearance in more than 30 countries, usually leaving a body count wherever it goes.

The fungus mostly sticks to healthcare settings, stealing into the blood of vulnerable patients where it causes invasive infections marked by nondescript fever and chills. It’s commonly resistant to multiple drugs, and some isolates have been found to resist all three classes of antifungal drugs, making it extremely difficult if not impossible to cure. Experts estimate that C. auris infections have a fatality rate somewhere between 30% and 60%. It’s hard to say for sure because many of its victims are seriously ill before they get infected, making it tricky to determine an individual cause afterward.

While the threat is clear, much about C. auris infections has been murky—including how it spreads from one victim to another. Researchers have found it loitering on hospital mattresses, furniture, sinks, and medical equipment, but they haven't determined how it got there. Once it is present, however, it’s a tough bug to annihilate. The fungal cells can form tight, hardy clumps that can live on plastics for at least two weeks and can go into a metabolically dormant phase for a month.

Torrential terror

For the new study, researchers at the Centers for Disease Control and Prevention and the City of Chicago Public Health Department tried to pin down how it gets onto those surfaces, which they hope can lead to a way to prevent its dispersal. They conducted their work in a ventilator-capable skilled nursing facility currently battling an outbreak, which started with a single case in March of 2017. Despite rigorous decontamination efforts, including bleaching surfaces and wiping down patients, 71 percent of residents have now tested positive for the fungus.

The researchers hypothesized that the fungus spreads by sloughing off of infected patients’ skin. Although the C. auris usually presents in a bloodstream infection, researchers have found it on the skin of healthy people. And such skin shedding would be a relatively easy explanation for how it scatters in healthcare facilities.

The researchers swabbed the skin of 28 residents and their rooms, fishing for living fungal cells and the strain's genetic fingerprints. They found plenty of both. Residents’ skin was loaded with the fungus, with some skin swab concentrations measuring in at an equivalent of more than 10 million fungal cells per milliliter. Importantly, the researchers found that the amount of fungal contamination in each resident’s room strongly and positively correlated with the amount festering on the resident’s skin. That is, the more skin fungus, the more room contamination.

The finding supports the hypothesis that skin shedding is the primary means by which C. auris gets around. The researchers are hopeful that the data link can help direct better decontamination and infection control efforts.

As of April 30, the CDC reports 654 confirmed cases in 2019 across a dozen states, with 30 additional probable cases. Screening in nine states has identified another 1,207 patients carrying the fungus without an infection.