Scientists have uncovered a new survival strategy used by Candida auris (C. auris), a drug-resistant fungus that has become one of the world’s most concerning healthcare-associated pathogens. New research suggests the fungus can hide inside hair follicles, allowing it to evade the immune system before potentially entering the bloodstream in vulnerable patients.
The findings offer fresh insight into why Candida auris can persist on the skin for months and spread in hospitals and long-term care facilities. They also highlight the challenges of treating infections caused by the fungus, which the US Centers for Disease Control and Prevention (CDC) classifies as an “urgent antimicrobial resistance threat”.
What is Candida auris?
Candida auris is an emerging species of yeast first identified in 2009. Unlike many common fungal infections, it is particularly concerning because it can:
- Resist multiple antifungal medications.
- Survive on surfaces for weeks.
- Spread rapidly in healthcare settings.
- Cause severe bloodstream infections in vulnerable patients.
The fungus primarily affects people with weakened immune systems or those receiving long-term medical care, including patients in hospitals, intensive care units, and nursing homes.
According to the CDC, Candida auris infections have been reported in numerous US states, with ongoing surveillance tracking new cases each year.
What did the new study discover?
Researchers found that Candida auris can take refuge inside hair follicles, creating a protected environment where it can avoid normal immune defenses.
In laboratory experiments using mice, scientists compared Candida auris with the more common fungus Candida albicans.
They observed striking differences:
- Candida albicans was rapidly cleared by the immune system.
- Candida auris persisted on the skin for extended periods.
- The drug-resistant fungus accumulated within hair follicles rather than remaining only on the skin surface.
This hidden reservoir may explain why the organism can colonize patients for months without causing immediate symptoms.
How does the fungus evade the immune system?
The study found that Candida auris appears to manipulate the body’s immune response.
Normally, fungal infections trigger a protective immune pathway involving IL-17, which helps repair skin and eliminate pathogens.
Instead, researchers found that Candida auris activated interferon gamma, an immune signal more commonly associated with fighting viral infections.
The fungus also alters its outer cell wall by exposing more chitin, a structural molecule that appears to influence how the immune system responds.
According to the study’s co-senior author, Dr. Suzanne Noble of the University of California, San Francisco (UCSF), the fungus effectively transforms the skin into an environment where it can persist.
How does Candida auris spread?
Unlike many fungal infections acquired in the community, Candida auris spreads primarily in healthcare settings.
Transmission can occur through:
- Direct contact with colonized patients.
- Contaminated medical equipment.
- Shared healthcare environments.
- Surfaces where the fungus can survive for prolonged periods.
People who carry the fungus on their skin often have no symptoms, but they can unknowingly transmit it to others.
Who is most at risk?
Healthy people rarely develop serious illness from Candida auris.
The highest-risk groups include:
- Intensive care patients.
- Nursing home residents.
- People with weakened immune systems.
- Patients using ventilators or catheters.
- Individuals with multiple underlying medical conditions.
When the fungus enters the bloodstream or internal organs, it can cause invasive infections that are difficult to treat.
What symptoms can invasive Candida auris cause?
People who are merely colonized often experience no symptoms.
However, invasive infections may cause:
- Persistent fever.
- Chills.
- Fatigue.
- Low blood pressure.
- Rapid heart rate.
- Signs of sepsis.
Because many affected patients are already critically ill, diagnosing Candida auris can be challenging.
How deadly is Candida auris?
The CDC reports that invasive Candida auris infections are associated with high mortality rates, particularly among patients with serious underlying illnesses.
Some studies have found mortality rates approaching 60%, but experts caution that these figures do not necessarily mean the fungus is the direct cause of death. Many patients have multiple severe medical conditions that contribute to their outcomes.
For that reason, mortality statistics should be interpreted carefully.
Can Candida auris be treated?
Treatment depends on the patient’s condition and whether the fungus has caused an active infection.
Doctors generally use echinocandins, a class of antifungal medications, as the first-line treatment. However, some strains have developed resistance to one or more antifungal drug classes, making infections more difficult to manage.
Researchers say there is currently no universally effective method for permanently eliminating Candida auris colonization from the skin, underscoring the importance of infection prevention in healthcare settings.
Why this discovery matters
The finding that Candida auris can hide inside hair follicles provides researchers with a possible explanation for why the fungus persists despite the body’s immune defenses.
Understanding this survival mechanism could eventually help scientists develop:
- Better antifungal therapies.
- Improved skin decolonization strategies.
- New approaches to preventing hospital outbreaks.
- More targeted immune-based treatments.
While the discovery does not immediately change clinical care, it offers valuable insight into one of the world’s fastest-growing antimicrobial resistance threats.
TL;DR
Scientists have discovered that the drug-resistant fungus Candida auris can hide inside hair follicles, helping it evade the immune system and persist on the skin. The fungus primarily threatens hospitalized and immunocompromised patients and can cause life-threatening bloodstream infections. The new findings improve scientists’ understanding of how Candida auris survives and may inform future treatments, but they do not suggest a new route of transmission for the general public.