As if the strike zone were not big enough, nature keeps throwing spitballs at us. One such pitch is a relatively new fungal infection, Candida auris. The pathogen was first identified in a Japanese patient in 2009. Unlike most Candida species, C. auris is often resistant to many antifungal drugs. It can persist on surfaces for weeks and spread easily in healthcare settings.
It becomes a health problem when it colonizes subjects whose health is fragile before infection. Thus, it affects hospitalized patients, ICU patients, those with central lines, ventilators, or catheters, people with weakened immune systems, and residents of nursing homes or long-term acute care facilities. Thus, it is a disease of opportunity.
In an update posted on its website on Dec. 27, the Centers for Disease Control and Prevention said that during 2025, 7,702 cases of Candida auris were confirmed in 30 states. Nevada and California reported more than 2,000 cases each, while Texas and Illinois confirmed more than 800 and 600 cases, respectively. It has also been reported in dozens of countries.
DNA analysis of four distinct but drug-resistant strains of C. auris indicates an evolutionary divergence taking place at least 4,000 years ago, with a common leap among the four varieties into drug-resistance, possibly linked to widespread azole-type antifungal use in agriculture. This conclusion, however, remains speculative.
More than 90% of C. auris isolates are resistant to fluconazole, and as high as 73% of C. auris isolates are resistant to voriconazole, while other triazoles display better activity. Of isolates, 13% to 50% were reported to be resistant to amphotericin B, but most cultured organisms are susceptible to echinocandins. Echinocandins are a class of antifungal drugs that inhibit the synthesis of β-glucan in the fungal cell wall via noncompetitive inhibition of the enzyme 1,3-β-glucan synthase.
The fungus can colonize the skin of healthy individuals without causing disease. It can spread by contact with those with weakened immune systems and cause serious, often lethal disease. Thus, it can easily spread from healthy subjects via direct contact to patients already ill with life threatening results. Typical manifestations of infection with this organism are sepsis, wound infections, and otitis. Mortality of people with C. auris bloodstream infections ranges from 30 to 60%.
Cases have increased markedly since COVID-19, likely due to strained infection-control practices. It’s now considered an urgent antimicrobial resistance threat by the CDC. Infection control requires strict isolation. Special disinfectants are needed to kill the fungus on affected surfaces. Outbreaks are difficult and costly to control.
As there are many more carriers of the organism compared to infected patients, strict isolation of susceptible subjects is impossible. There are millions of chronically ill people in the US who are not only at risk from C. auris, but also from an army of other infectious pathogens. The best we can do is increase awareness of this problem so it can be recognized promptly and treated appropriately.
While a vaccine has been shown to be effective in mice, there is currently no human vaccine available. C. auris is not dangerous to the general public, but it represents a serious threat within healthcare settings, combining drug resistance, environmental persistence, and ease of transmission.
