There is little doubt that Candida auris (C. auris) infections are a growing threat. But the yeast is not resulting in the Zombie Apocalypse, nor is it a pressing problem for most of us. Let’s unpack the heated rhetoric.
First, I apologize that this article's basis is not the article published in the Annals of Internal Medicine (see Sources). The article is paywalled. My reporting is based on the report’s synopsis by the publisher and data posted by the CDC.
National surveillance by the CDC has found increasing numbers of cases of C. auris in the U.S. since the first case was detected in 2016. C. auris was first identified in Japan in 2009 and spread over six continents and 40 countries. It is particularly problematic for several reasons:
- Most fungi do not thrive at human physiologic temperatures. C. Auris is an exception and can grow at elevated temperatures that we would associate with fever, 104°F. C. Auris also tolerates high salt concentrations. The organism can also form a biofilm to provide a protective niche as it resides on and in us. Combining the enhanced thermal and osmotic tolerances and the ability to create a protective biofilm allows C. auris to live on surfaces for weeks, making them resistant to some of our typical cleaning measures.
- There is widespread resistance to first-line therapy, echinocandins, an anti-fungal. There is already significant resistance to older medications, for example, fluconazole with a 91% resistance or Amphotericin with a 12% resistance. To give you a sense of just how uncomfortable the use of these agents can be, the slang term for Amphotericin is “Amphoterrible” or alternatively, “shake and bake.” Resistance to the echinocandins is approximately 12%.
- Infection with C. auris carries a very high mortality, upwards of 33 to 45%.
- C. auris is found in healthcare settings, hospitals, and especially long-term care (LTC) centers. These LTCs frequently care for those individuals with debilitating illnesses, such as those requiring permanent mechanical ventilation. These patients often are immunocompromised, and many are colonized with C. auris on their skin. Colonization, per se, is not infection, but in the setting of being immunocompromised and having various medical “tubes” piercing your skin, e.g., a tracheostomy tube for mechanical ventilation, these fungi can infect. The mortality data quoted is for blood-borne C. auris infections, but they can also cause wound and other infections.
To put a pin in it, these infections are increasing in healthcare settings involving the particularly frail and vulnerable, causing significant mortality. We have few, if any, medications that effectively treat an infection.
Since 2016 there have been 3,270 clinical infections and 7,413 positive screenings in which the fungus is detected but not causing an infection.
- Clinical cases rose from 476 in 2019 to 1,471 in 2021 – the rate of increase accelerated from “a 44 percent increase in 2019 to a 95% increase in 2021.” Most of these cases are in the susceptible living in medical facilities with “indwelling devices or mechanical ventilators.”
- Screening cases tripled between 2020 and 2021 for a total of 4,041. Similarly, screening has intensified with an 80% and 200% increase during the same interval.
- Resistance to first-line therapy increased three-fold
The why of these increases is multifactorial. There is more screening to enhance detection, and despite the pandemic's lessons, there continues to be “poor general infection prevention and control (IPC) practices in healthcare facilities.” The CDC has classified this as an urgent threat, along with four other infections.  To provide context, Clostridioides difficile (c. difficile), another and far more significant urgent threat, is responsible for “223,900 infections per year [and] 12,800 deaths per year.”
What to do
The CDC report on Antibiotic Resistance published in 2019 offers four helpful suggestions
- Stop referring to a post-antibiotic era – it is already upon us
- Stop the blame game – this is global and impacts us all. There are no special villains
- Stop relying on new antibiotics – Dr. Shlaes has written extensively on this topic.
- Stop believing that antibiotic resistance is a problem “over there.”
We might also consider improving the care and cleaning associated with our long-term care facilities. There is difficulty with that course. First, it costs money to provide better staffing and wages, not just to require better infection control practices but oversee that it happens. Second, personal protective equipment and practices are a hassle and impede care. It is like infrastructure, something we all want but will not readily pay for.
The increasing incidence of C. auris in the facilities that care for our most frail is our early warning, just like the rising cases and deaths from COVID in our nursing homes foretold the coming pandemic. We can take bold measures, removing all antibiotics not used to treat illness from our food supply. We can also take strategic steps, funding better conditions and practices in the facilities caring for our weakest. Unfortunately, what we and our “leadership” will do, is feel a momentary trepidation or conceive of a Big Government conspiracy to share around social media.
 Carbapenem-resistant Acinetobacter, Carbapenem-resistant Enterobacterales (CRE), Drug-resistant Gonorrhea, and Clostridioides difficile.
Sources: Worsening Spread of Candida auris in the United States, 2019 to 2021 Annals of Internal Medicine DOI: 10.7326/M22-3469
Is the superbug fungus really so scary? A systematic review and meta-analysis of global epidemiology and mortality of Candida auris Annals of Internal Medicine DOI: 10.7326/M22-3469