Professor Rodney E. Rohde, a public health and clinical microbiology expert at Texas State University, warned in article for The Conversation of the growing threat of fungal resistance — a problem drawing much less attention than antibiotic resistance.
Athlete’s foot, thrush, ringworm and other ailments are caused by fungi, and some are serious risks to health and life. Among these is Candida auris, a pathogenic fungus. Fungi generally have not caused major disease, so there is a lack of funding in this area and there are limited antifungal agents that can treat C. auris.
Most fungal infections around the world are caused by the genus Candida, particularly the species called Candida albicans. But there are others, including Candida auris, which gets its name ‘auris’, Latin for ear, because it was first identified from an external ear canal discharge in 2009.
Candida normally lives on the skin and inside the body, such as in the mouth, throat, gut and vagina, without causing any problems. It exists as a yeast and is thought of as normal flora, harmless microbes. However when the body is immuno-compromised, these fungi become opportunistic pathogens, something happening around the world with multidrug-resistant C. auris.
The threat of Candida auris
C. auris infections, or fungaemia, have been reported in 30 or more countries. They are often found in the blood, urine, sputum, ear discharge, cerebrospinal fluid and soft tissue, and occur in people of all ages. According to the US Centers for Disease Control, the mortality rate in the US has been reported to be between 30% to 60% in many patients who had other serious illnesses. In a 2018 review of research on the global spread of the fungus, researchers estimated mortality rates of 30% to 70% in C. auris outbreaks among critically ill patients in intensive care.
Recent surgery, diabetes and broad-spectrum antibiotic and antifungal use are risk factors. Furthermore, immuno-compromised patients are at greater risk than those with healthy immune systems.
C. auris can be difficult to identify with conventional microbiological culture techniques, which leads to frequent mis-identification and under recognition. This yeast is also known for its tenacity to easily colonise the human body and environment — including medical devices. People in nursing homes and patients with catheters, on ventilation etc seem to be at highest risk.
The CDC has set C. auris infections at an “urgent” threat level because 90% are resistant to at least one antifungal, 30% to two antifungals, and there are some resistant to all three available classes of antifungals. This multidrug resistance has led to outbreaks in health care settings, especially hospitals and nursing homes, that are extremely difficult to control.
The double threat of COVID and C. auris
For hospitalised COVID patients, antimicrobial-resistant infections may be a particularly devastating risk. The mechanical ventilators often used to treat serious COVID are breeding grounds and highways for entry of environmental microbes like C. auris. Further, according to a September 2020 paper, hospitals in India treating COVID have detected C. auris on surfaces including “bed rails, IV poles, beds, air conditioner ducts, windows and hospital floors.” The researchers termed the fungus a “lurking scourge” amid the COVID pandemic. Termed ‘white fungus’, these fungal infections typically arise a week to 10 days after being in the ICU.
The same authors reported in a November 2020 CDC article that of 596 COVID-confirmed patients in a New Delhi ICU from April 2020 to July 2020, 420 patients required mechanical ventilation. Of these, 15 were infected with candidemia fungal disease and eight of those infected (53%) died. Ten of the 15 patients were infected with C. auris; six of them died (60%).
How to deal with this?
With fewer and fewer antifungal options, CDC is recommending a focus on preventing C. auris infections. This involves better hand hygiene and improving infection prevention and control in medical care settings, judicious and thoughtful use of antimicrobial medications, and stronger regulation limiting the over-the-counter availability of antibiotics.
Source: The Conversation
Journal information: Anuradha Chowdhary et al, The lurking scourge of multidrug resistant Candida auris in times of COVID-19 pandemic, Journal of Global Antimicrobial Resistance (2020). DOI: 10.1016/j.jgar.2020.06.003
