Candida auris, which spreads easily and can resist common treatments, poses a deadly infection risk to fragile and elderly patients.
Cases of a dangerous fungus resistant to common medicines have been spreading at an "alarming rate" across the United States since the start of the coronavirus pandemic, according to the US Centers for Disease Control and Prevention.
Cases of Candida auris, an emerging fungus considered an urgent antimicrobial resistance (AMR) threat, tripled in the US over just three years, and more than half of the country's states have now reported it.
Also concerning was a tripling in 2021 of the number of cases resistant to echinocandins, the antifungal medicine most recommended for the treatment of C. auris infections, the health agency reported.
The COVID-19 pandemic likely drove part of the overall increase in cases, CDC researchers wrote in the paper, published this week by Annals of Internal Medicine.
Hospital workers were strained by coronavirus patients, and that likely shifted their focus away from disinfecting some other kinds of germs, they said.
C. auris is a form of yeast that is usually not harmful to healthy people but can be a deadly risk to fragile hospital and nursing home patients. It spreads easily and can infect wounds, ears, and the bloodstream.
CDC has deemed C. auris an urgent AMR threat, because it is often resistant to multiple antifungal drugs, spreads easily in healthcare facilities, and can cause severe infections with high death rates.
C. auris was first identified in Japan in 2009 and has been seen in more and more countries. The first US case occurred in 2013, but it was not reported until 2016. That year, US health officials reported 53 cases.
The new study found cases have since continued to shoot up, rising to 476 in 2019, to 756 in 2020, and then to 1,471 in 2021.
Doctors have also detected the fungus on the skin of thousands of other patients, making them a transmission risk to others.
Many of the first US cases were infections that had been imported from abroad, but now most infections are spread within the US, the authors noted.
What are the symptoms of C. auris infection?
People who get infected with C. auris are often already sick from other medical conditions, so it can be tricky to determine whether they have been infected with this fungus.
According to CDC, the most common symptoms of invasive Candida infection are fever and chills that don’t improve after antibiotic treatment for a suspected bacterial infection. Other symptoms can develop if the infection spreads to other parts of the body, such as the heart, brain, eyes, bones, or joints.
Only a laboratory test can diagnose C. auris infection.
People who are very sick, have invasive medical devices such as ventilators or have long or frequent stays in healthcare facilities are at particular risk for C. auris infection, CDC said in its report.
"The rapid rise and geographic spread of cases is concerning and emphasises the need for continued surveillance, expanded lab capacity, quicker diagnostic tests, and adherence to proven infection prevention and control," CDC epidemiologist Dr Meghan Lyman, lead author of the study, said in a statement.