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Candidozyma (Candida) auris

Candida, a genus of yeasts, is the most common cause of fungal infections worldwide. Many species of Candida are harmless. Approximately 90 % of infections are caused by five species: Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis, and Candida krusei. Candida albicans is the most commonly isolated species, causing various infections from thrush to bloodstream infections.

In 2009, Candida auris was first isolated from the external ear canal (‘Auris’- the Latin word for the ear) of a patient in Japan and has now emerged as a pathogenic fungal infection causing healthcare-associated infections. Due to better survival in the environment, prolonged outbreaks have been reported in many countries. It is considered a serious threat to global health because it is resistant to fluconazole, the first-line antifungal therapy, and often to multiple antifungal agents, with some strains resistant to all three available antifungal classes. In addition, it is difficult to identify using standard laboratory methods, and misidentification may lead to inappropriate management (see below).

Clinical infection: Risk factors included susceptible patients across all high-risk units. The clinical presentation of C. auris infections is similar to that of other Candida species, which can cause invasive infections with up to 60% mortality. Clinical conditions reported include bloodstream infections (fungemia), urinary tract infections, surgical wound infections, burn infections, skin abscesses (related to catheter insertion), ear infections, myocarditis, meningitis, and bone infections.

As with other Candida spp., they can also be isolated from non-sterile body sites such as the genitourinary tract, skin and soft tissues, and lungs, where they colonise rather than cause infection, especially with the use of broad-spectrum antibiotic therapy. Treatment of C.auris should be started only in the presence of clinical disease and avoided in colonised patients.

Laboratory Testing: Most microbiology laboratories worldwide do not routinely identify Candida to the species level or test antifungal susceptibility when isolates are from superficial sites. Even when species identification is performed, many commercial biochemical kits and automated testing methods can misidentify C. auris as other Candida species, making its detection and control difficult. Real-Time PCR and rapid identification from cultured isolates using MALDI-TOF mass spectrometry are the most effective methods for detecting early and accurately. As C.auris is commonly resistant to fluconazole, a first-line antifungal, and can also develop resistance to other classes of antifungal agents, antifungal susceptibility testing should be performed.

Infection Control Precautions: Unlike other Candida spp., C. auris is not considered part of the normal human microbiota. They can grow at higher temperatures than other fungi and tolerate high salt concentrations. These characteristics enable it to survive and remain in the environment (dry and wet) for extended periods, thus providing opportunities for colonisation and onward transmission. In addition to increased survival in the environments, they tend to form biofilm on plastic, metal, and medical equipment. Therefore, once established, the outbreaks are difficult to control. As a result, prompt identification of organisms, isolation of patients, and IPC  are necessary for all hospital patients. Strategies to prevent and control the organism include:

  • Prudent use of antibiotics: Use antibiotics prudently and avoid using unnecessary antibiotics (esp. broad spectrum) to prevent the colonisation of Candida spp.
  • A Screening policy: This is based on local risk assessments. Screening of the patient is recommended for (i) colonised or infected patients transferred from a hospital where C.auris with ongoing infection and/or colonisations is endemic,(ii) patients transferred from any hospitals outside of N. Ireland (with history of hospitalisation within the past 12 months ), and (iii) high-risk patients identified during triage as part of IPC risk assessment. These patients should be isolated immediately in a single room until screening results are available.
  • Patient placement: Patient with confirmed colonisation and/or infection with C. auris should be isolated in a single room with ensuite facilities with standard and contact precautions.
  • Hand hygiene: Hand hygiene with alcohol-based hand rubs (ABHRs) is recommended for physically clean hands and is the most effective for inactivating Candida species, including auris. Use isopropyl or ethanol (70% alcohol) and rub hands thoroughly for at least 30 seconds, covering all areas of the hands, with special emphasis on the thumbs and fingertips. In contrast, washing with soap and water removes visible soiling and therefore applies to visibly dirty hands but does not reliably inactivate Candida, which are more tolerant of aqueous cleansing than many bacteria.
  • Colonisation: Colonisation with C.auris may persist for many months and possibly years, and as a result, these patients may act as a source of transmission to other patients, mainly via contaminated hands, use of contaminated gloves, items, equipment and frequent hand touch of environmental surfaces. Decolonisation with antiseptics is not effective and should not be used.
  • Decontamination of items and equipment: Because C.auris is spread through contact with contaminated surfaces and fomites, shared multi-use patient equipment must be thoroughly cleaned, disinfected, and/or sterilised between patients. Consider using dedicated items such as a stethoscope, thermometer, sphygmomanometer, and tourniquet.
  • Environmental cleaning: Both infected and colonised patients substantially contaminate the environment and equipment where the  auris  can remain for weeks in the healthcare environment on various surfaces. The organism is resistant to commonly used disinfectants (e.g., quaternary ammonium compounds); therefore, chlorine-based disinfectants (e.g., 1000 ppm of hypochlorite solution) are recommended for environmental cleaning.

Once the patient has left the environment, terminal cleaning should be undertaken. Consideration should be given to discarding less expensive items that are difficult to decontaminate or using single-patient use devices such as blood pressure cuffs. Stocks of single-use items in the immediate patient environment should be discarded.

Guidance and supporting materials: