Candida auris Surveillance, Qualitative Real-Time PCR, Axilla/Groin, Nares
Test code: 10153
Clinical use
Clinical background
C auris is a multidrug-resistant fungus and an emerging cause of infection in hospital and other healthcare settings. The US Centers for Disease Control and Prevention (CDC) has reported substantial year-to-year increases in cases since C auris was made a nationally notifiable disease: from 329 cases in 2018 to 2,377 cases in 2022.1 Moreover, the number of cases reported in 2022 does not include 5,754 patients carrying C auris on external body sites, referred to as colonization.1 Colonization is a risk factor for bloodstream infection (candidemia), and about 5% to 10% of known colonized patients develop invasive infections (candidiasis).2,3 The most common sites of colonizationare the axilla (armpit) and groin, but the nares (nostrils) may also be colonized.
Transmission of C auris primarily occurs in healthcare settings through physical contact with contaminated surfaces or through person-to-person contact. Nosocomial transmission occurs via contaminated medical equipment, such as catheters or feeding tubes, and contributes to significant risk of infection among long-term patients in healthcare settings or intensive care units, and among people with serious underlying medical conditions.
Detection of C auris colonization may help reduce nosocomial transmission. The CDC recommends swabbing the axilla and groin and also identifies the nares (and hands) as collection sites having potential for improving the identification of colonized patients.4 Processing and detection can involve either culture-based or real-time PCR (RT-PCR) methods. Culture-based methods are considered the gold standard because they allow for isolate recovery and susceptibility testing5; however, they do not differentiate C auris from other Candida species or unidentifiable organisms.6,7 Culture-based methods also have 5- to 7-day turnaround times, which may be too long when rapid identification of C auris is needed to implement public health measures to control the spread of infection.6,8
RT-PCR addresses some constraints of culture-based methods for detecting C auris colonization. Species-specific RT-PCR can differentiate C auris from other closely related species (eg, Candida albicans, Candida glabrata) and in some cases can detect C auris when culture does not.9 For example, recovery of C auris by cultureis greatly reduced if swabs have been stored for longer than 72 hours; however, dead C auris can be detected by RT-PCR, which enables retrospective evaluation of swabs that have been stored for a long time.8,10,11 Furthermore, RT-PCR can be performed much faster, with results generally available in 2 to 3 days.
Quest Diagnostics offers the Candida auris Surveillance, Qualitative Real-Time PCR, Axilla/Groin, Nares test (test code 10153), a screening test that detects C auris DNA in surveillance specimens.
Individuals suitable for testing
Method
Interpretive information
A detected result indicates that C auris DNA was detected in the surveillance specimen for C auris colonization. About 5% to 10% of known colonized patients develop invasive infections (candidiasis).2,3
A not detected result indicates that C auris DNA was not present in the surveillance specimen above the limit of detection of the assay (5 CFU/mL).
This assay is intended for screening of C auris colonization from external body sites and should not be used for patient monitoring, for therapy decisions, or as a test of cure.
References
Content reviewed 04/2023
Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.
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