Researchers Pinpoint Cause of Candida auris Outbreak in the United Kingdom

Researchers have found that an outbreak of Candida auris (C. auris) infections that occurred in intensive care units in the United Kingdom may be linked to multi-use patient equipment, including thermometers.

C. auris is a pathogenic yeast that can cause serious bloodstream infections and even death. Candida yeasts often live in the intestinal tract and can be found on mucous membranes and skin without resulting in infection. However, under certain conditions, Candida can multiply and grow in the mouth, throat, or esophagus, leading to infection. Less serious cases of candidiasis typically affect these areas, causing generally mild symptoms that can be treated with antifungal medication. In more severe cases, however, this yeast can enter the bloodstream and lead to invasive candidiasis, a serious condition that can affect the heart, brain, eyes, bones, as well as other parts of the body. Individuals who are already sick from other conditions are more likely to get Candida infections, and in health care facilities such as hospitals and nursing homes, the yeast can spread from infected patients as well as contaminated surfaces and equipment, making these likely locations of outbreaks.

According to the Centers for Disease Control and Prevention (CDC), C. auris was only discovered in 2009 and has since gone on to become an emerging global health concern due to the pathogen’s resistance to antifungal medications. In addition, these infections are frequently misattributed to other fungal pathogens and require specialized medical equipment for accurate diagnosis. In new research from the European Society of Clinical Microbiology and Infectious Diseases, an outbreak of C. auris that occurred in the Neurosciences Intensive Care Unit (NICU) of Oxford University Hospitals has been linked to axillary thermometers used in multiple patients.

In the new findings, recently presented at the 28th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID), researchers examined 70 patients colonized or infected with C. auris from February 2, 2015 to August 31, 2017. Of those patients, 66 patients (94%) were admitted to the NICU before being diagnosed. While no patients died as a direct result of C. auris infection, 7 patients developed invasive infections. Axillary thermometers used to measure body temperature in the armpit had been used in 57 of the 66 patients (86%). Researchers determined that after controlling for other factors — such as length of stay in the NICU and how unwell the patient reported feeling – use of the thermometers was a strong risk factor for C. auris. They went on to culture samples of the fungal pathogen from the equipment and detect it on the surface of temperature probes with a scanning electron microscope, matching the surface samples genetically to the patient samples.

“Despite a bundle of infection control interventions, the outbreak was only controlled following removal of the temperature probes,” said presenting author David Eyre, DPhil. “This reinforces the need to carefully investigate the environment, and in particular multi-use patient equipment, in any unexplained healthcare-associated outbreak.”

In a study published in January 2018, researchers reported on the development of a new antifungal compound that proved effective against C. auris in the laboratory as well as in mice. The drug is the first in a new class of antifungals, and researchers found it to be more potent against 16 strains of the fungal pathogens than 9 other antifungals currently available.