The Deadly, Drug-Resistant Fungal Infection Outbreak That's Spreading In The US

Drug-resistant infections are a growing problem that's characterized by dangerous fungi, parasites, bacteria, and viruses that do not respond to medications. Also known as antimicrobial resistance (AMR), drug-resistant infections in humans are largely driven by the overuse of antimicrobial medications. The World Health Organization considers AMR a major public health issue worldwide because of the risk of disease spread, as well as associated severe illnesses and deaths. Some of the most common sources of AMR are antibiotic resistance to Clostridium difficile, Mycobacterium tuberculosis, and methicillin-resistant Staphylococcus aureus. While bacterial AMR rightfully gets a lot of attention, certain drug-resistant fungal infections have also been on the rise in recent years. One example is a fungal infection caused by Candidozyma auris. This particular species (which is a fungus, not a mold) emerged in 2009, and has since become an ongoing healthcare concern because of its easy spread, overall invasiveness, and poor reception to conventional antifungal drugs.

Previously known as Candida auris, C. auris belongs to a group of yeasts that cause fungal infections known as candidiasis. C. auris first colonizes on the skin and mucous membranes. Related infections are considered among the invasive types of candidiasis, which are much more severe due to their ability to infect the bloodstream and internal organs. Like other types of invasive candidiasis, C. auris is primarily spread via healthcare settings, with hospitals particularly affected. What makes this species more challenging is its long lifespan of several weeks to months. Worse, it can survive on virtually any surface in a healthcare setting, including diagnostic equipment, hospital beds, doors, and computers.

After first being identified in Japan in 2009, C. auris has since been detected in more than 60 countries worldwide, according to the National Center for Biotechnology Information (NCBI). This includes the U.S., where the first case was discovered in 2016. Although these infections are spreading in the U.S. and around the world, the exact global prevalence isn't known. However, the Centers for Disease Control and Prevention (CDC) has been monitoring new cases as well as the overall rate of C. auris infections. Per the agency's latest data report, there were 6,304 reported cases of C. auris, which indicates that the infection is still spreading in the U.S. While this is a new record compared to previous years, the rate of overall cases has been declining since 2022.

Yet due to its long lifespan and ease of spread, it's easy to see why this fungal infection has become an ongoing issue in the U.S. C. auris also gained more traction during the COVID-19 pandemic due to more exposure via increased numbers of hospitalizations. Unfortunately, C. auris has a high mortality of between 30% and 60%, per the NCBI. Infection severity, age, and comorbidities can all play a role in the prognosis of this illness.

While prompt detection and treatment is paramount to preventing and eradicating infections, the situation with C. auris is more complex. Early symptoms of infection are non-specific, and can include fever and chills. Other symptoms are variable, depending on which organs the infection spreads to, and whether or not it affects the bloodstream. The only way to confirm a C. auris infection is through lab testing.

Aside from its invasiveness and ability to live on surfaces for a long time, C. auris is so concerning because of its ability to resist several types of antifungal drugs. Once a doctor makes this diagnosis, they may prescribe intravenous antifungal medications. Unfortunately, C. auris is also notoriously resistant to antifungals, even in those with no prior history of taking them. According to the CDC, scientists are also investigating the possibility that AMR strains of C. auris may exist and spread to others, which makes treatment even more challenging.

People with weakened immune systems are at a greater risk of severe illness from C. auris infections. This includes individuals living with HIV infections or recent organ transplants, as well as those undergoing cancer treatments. Recent hospitalization or surgery are other risk factors. C. auris infections are not as common in healthy individuals. Furthermore, not everyone who develops the infection will automatically experience severe illness. Still, patients who carry C. auris but are not actively sick can spread the yeast to surfaces just as readily as those who have infections. This fact undoubtedly contributes to the easy spread of this fungal infection, and subsequent infections in people who are more vulnerable to severe (and potentially life-threatening) illnesses.