Candida auris
Candida, a genus of yeasts, is the most common cause of fungal infections worldwide. Many species of Candida are harmless. Approximately 90 per cent of infections are caused by five species: Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis, and Candida krusei. Candida albicans are the most commonly isolated species causing a range of conditions 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. 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 is often resistant to multiple antifungal agents, with some strains being resistant to all three available classes of antifungals. In addition, it is difficult to identify with standard laboratory methods, and misidentification may lead to inappropriate management.
Clinical infection: The risk factors and clinical presentation of C.auris infections are similar to those of other Candida species, which can cause invasive infections with up to 60 per cent mortality. Clinical conditions that have been 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 are colonising rather than causing actual infection and can occur because of 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 species level nor test susceptibility to antifungals if the isolates are from superficial sites. Even if species identification is undertaken, many biochemical commercial kits and automated testing methods can misidentify C. auris for other Candida species, making detecting and controlling this pathogen difficult. As C. auris are 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: As with most Candida spp. , C.auris arises from the host’s microflora rather than by acquisition from another person. However, C. auris is not considered a resident commensal organism and is not typically present within the human gastrointestinal tract. In addition, it has the propensity to spread. Therefore, it is essential to quickly identify it in hospitalised patients so that special precautions can be taken to stop its spread. Strategies to prevent and control the organism include:
- Prudent use of antibiotics (esp. broad spectrum) to prevent the colonisation of yeasts.
- Screening policy based on local risk assessments. Screening is recommended in units with ongoing infection and/or colonisations or identification of a newly infected or colonised patient.
- Colonisation with aurismay persist for many months and possibly indefinitely and is difficult to eradicate. Colonised patients may also be a source of transmission to other patients and environmental contamination.
- Patient placement: Colonised or infected patients who have been transferred from a hospital where auris is endemic or a hospital abroad should be isolated until screening results are available. Ideally, they should be isolated in a single room with ensuite facilities with standard and contact precautions.
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. In addition, C. auris might substantially contaminate the environment and equipment of colonised or infected patients and may persist in the healthcare environment on various surfaces. It can survive for 7 days on moist or dry surfaces and may remain viable for up to 4 weeks. Fungicidal products effective against other Candida species and quaternary ammonia compounds may not necessarily be effective against C. auris. Hypochlorite (1,000 ppm available chlorine ) is recommended for environmental disinfection of the patient’s room and other areas where care is received and should be performed daily. 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
PHE: Guidance for the laboratory investigation, management and infection prevention and control for cases of Candida auris
PHE: Candida auris infection control in community care settings
Rapid Risk Assessment. Candida auris in healthcare settings: Europe
Infection Prevention and Control for Candida auris: CDC
https://www.cdc.gov/fungal/candida-auris/c-auris-infection-control.html