C auris: A Rare but Growing Menace in Health Care Settings

A fungal pathogen first identified just 10 years ago is causing outbreaks in more and more health care settings, disproportionately affecting the elderly and immunocompromised. Candida auris can be extremely difficult to eradicate once entrenched, and part of the problem is that hosts shed it via skin cells. Once shed, the pathogen can live for weeks on dry surfaces.

A team of investigators at the US Centers for Disease Control and Prevention (CDC), working with the City of Chicago’s Public Health Department, obtained skin swab samples from 28 patients at a ventilator-capable skilled nursing facility in Chicago experiencing an outbreak of C auris. In addition, they collected 2 samples per patient from hospital surfaces, including the patients’ bed rails, window sills, and door knobs.

Although the subjects had various amounts of C auris colonizing their skin, the investigators found that patients with higher concentrations of the pathogen shed a greater amount of it onto their beds and into their immediate environments. This gave the investigators a better idea of the mechanism by which C auris spreads and provided them with information that will hopefully enable better infection-control strategies.

C auris is a stubborn pathogen that can be quite dangerous for people who are immunocompromised. It is often misidentified, is multidrug-resistant, and may remain even after surfaces are disinfected. Scientists say it’s not necessarily C auris itself that is directly responsible for the fatality rate of up to 50% in people who contract it, but the fact that it enables other infections to take hold. “These can be bloodstream infections leading to sepsis,” Joe Sexton, PhD, a post-doctoral fellow in the CDC’s Mycotic Diseases Branch and the study’s lead author, told Contagion®. “It can disseminate into the eye, kidney, lung, heart valve, and brain.”

To be clear, the current risk of contracting C auris is low for most people, even those who reside in traditional nursing homes. Most concerning are the outbreaks at long-term facilities “[that] have a much more medically complicated population,” Sexton said, referring to patients who are on ventilators or are otherwise not mobile.

As of April 30, 2019, the CDC had identified 654 clinical cases of C auris, primarily in New York City, New Jersey and Chicago. In addition, screening in 9 states revealed 1201 patients who are colonized with the pathogen but are not showing symptoms of disease. While many states do not have a single identified case of C auris, and others such as California and Texas have only a handful, those numbers could change quickly as the disease moves from the East Coast towards the West. “The current evidence suggests that it’s truly emergent and it’s spreading fast,” Sexton noted.

Challenges ahead for clinicians and investigators include correctly identifying cases of C auris as early as possible, implementing effective infection-control strategies in affected facilities and prioritizing further study. “We’re still trying to catch up and learn so much about it,” Sexton said. “We’re working with these facilities to try to improve the way we respond. We’ve been surprised by [the pathogen’s] ability to spread in a healthcare setting, [and] it’s really important to continue research on how it spreads.”