Improvement in modern medicine and an increased case of immune-compromised patients, opportunistic yeast infections have become an immerging cause of morbidity and mortality in critically ill patients. Recently, some unusual opportunistic yeast species have increased, and other known rare yeasts have appeared more often in the last decade
Candida auris is a healthcare-associated yeast that causes invasive infections along with poor treatment outcome. Candida auris is difficult to treat as it is resistant to the first-line antifungal, fluconazole (FLC) and exhibits variable susceptibility to other azoles, amphotericin B (AMB), and echinocandins(A. Chowdhary, Voss, & Meis, 2016).The first case of Candida auris was isolated by Japanese scientists in 2009 from the external ear canal (auris means ‘ear’ in Latin) of an inpatient in a Japanese hospital, now Candida auris has identified in more than a dozen countries on five continents.
Typically, scientists diagnose fungal infections by growing the fungus from a person’s blood or other body fluids in a laboratory setting. However, Candida auris are difficult to identify and can be mistaken for other types of fungus. Special tests are sometimes needed to make a proper diagnosis . Several studies published recently indicate that Candida auris in routine microbiology laboratories remain an unnoticed pathogen, approximately 90% of the isolates characterized by commercial biochemical identification systems are misidentified primarily because of a lack of the yeast in their databases. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) is considered a more rapid and robust diagnostic technique for Candida auris identification(Anuradha Chowdhary, Sharma, & Meis, 2017). Several medications used by the physician to treat fungal infections are ineffective in treating Candida auris infections. In some cases, multiple antifungal medications at high doses might be needed to treat the infection .
At present, there are no Clinical and Laboratory Standards Institute (CLSI) or European Committee for Antimicrobial Susceptibility Testing (EUCAST) defined breakpoints for Candida auris susceptibility. CDC recommends that all Candida auris detected should undergo susceptibility testing and provides guidance for minimum inhibitory concentration (MIC) breakpoints based on related Candida species and expert opinion.
Fluconazole (tentative MIC breakpoint 32) is associated with high minimum inhibitory concentrations (MICs) and is likely almost always resistant. Echinocandins are the empiric drugs of choice for Candida auris infections in adults and children over the age of 2 months. Amphotericin B is less reliable, therefore should be considered for patients not responding to echinocandin therapy, depending on MIC results.
The overall crude mortality rate in-hospital of Candida auris candidemia ranges from 30% to 60%, and infections typically occur several weeks (10?50 days) after admission. Candida auris invasive infections represent a therapeutic challenge, and no consensus exists for optimal treatment. Some studies report breakthrough fungemia while on FLU, and this correlates with commonly reported high MICs (>32 ?g/ml), suggesting intrinsic resistance against this drug.
Still further clinical studies in humans are needed. It is important to note that resistance may develop on therapy and close clinical follow-up and potentially repeat MIC testing may be indicated for patients who are responding poorly to antifungal therapy.
The Centers for Disease Control and Prevention (CDC, 2017) is alerting healthcare providers because patients in various countries have been infected with Candida auris, a yeast that can lead to invasive infections.
Candida auris is concerning public health officials for the following three reasons:
1. Candida auris strain is multidrug-resistant, meaning that it is resistant to commonly used drugs to treat Candida infections.
2. It causes high death rate in hospitalized patients and spreads quickly.
3. It is hard to diagnose in the standard hospital laboratory; this means that cases could be misdiagnosed and inappropriately managed.
Candida auris cases continue to be found throughout the world, there is an urgent need for improved diagnostics, antifungal therapies, and infection control measures. PCR and real-time PCR assays to rapidly identify Candida auris have shown excellent accuracy in development and could be performed in laboratories that do not have the ability to perform MALDI-TOF or molecular sequencing techniques. The development of new antifungal medications with activity against Candida auris will be vital to controlling Candida auris as therapeutic options are already limited. SCY- 078, a novel triterpene glucan synthase inhibitor, is currently in phase III trials for invasive and mucocutaneous candidiasis and has recently shown promising activity in vitro against Candida auris. Finally, aggressive infection control measures are critical to reducing the spread of Candida auris. Antimicrobial stewardship, hand hygiene, and contact precautions will continue to be of paramount importance. More information is needed, however, about effective measures to reduce patient colonization and environmental contamination in healthcare facilities which have served as sites of ongoing transmission of this emerging pathogen.