Detecting Candida auris from surveillance swabs
This test should not be used to determine cure or to monitor response to therapy.
Real-Time Polymerase Chain Reaction (PCR)
C. auris
Swab
Specimen must arrive within 7 days of collection.
Specimen source is required.
Question ID | Description | Answers |
---|---|---|
SRCSR | Specimen Source |
Supplies: BD Eswab (T853)
Specimen Type: ESwab
Source: Axilla and groin composite
Container/Tube: ESwabs in liquid Amies medium
Specimen Volume: Swab
Collection Instructions:
1. Swab transport containers without charcoal must contain a pledget saturated with either Stuart's or Amies liquid media.
2. Swab used for this test cannot be shared with fungal culture. When fungal culture is ordered with this test, send separate swabs for each.
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.
See Specimen Required
Wood shaft or charcoal swab Clear semi-solid/solid media | Reject |
Culturette swab | Reject |
Clear semi-solid/solid media | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Swab | Refrigerated (preferred) | 7 days | |
Frozen | 7 days |
Detecting Candida auris from surveillance swabs
This test should not be used to determine cure or to monitor response to therapy.
Candida auris can cause serious, and sometimes fatal, infections, is often resistant to one or more classes of antifungal drugs, and inappropriate treatment may occur as it can be misidentified in the laboratory. In addition, C auris appears to be more resistant to disinfection than other yeasts, leading to prolonged survival in the environment, increasing the possibility of transmission in hospitals and nursing homes.
In December 2018, the Centers for Disease Control and Prevention (CDC) recommended that healthcare facilities implement routine surveillance screening of patients who have had an overnight stay in a healthcare facility outside of the US over the past year, particularly if the hospitalization was in a country with confirmed cases of C auris. The CDC also recommended considering screening of patients who have been hospitalized outside of the US and have a documented infection or colonization with a carbapenemase-producing gram-negative bacteria. These patients have frequently been found to have C auris colonization as well. A second group of people for whom screening is recommended includes healthcare workers who have been in close contact with patients who have previously unrecognized C auris infection or colonization.
The C auris polymerase chain reaction assay detects and identifies C auris combination groin/axilla surveillance swabs.
Not applicable
A positive result indicates the presence of Candida auris DNA.
A negative result indicates the absence of detectable C auris DNA.
A negative result does not rule out the presence of Candida auris because the organism may be present at levels below the limit of detection for this assay.
This assay detects C auris nucleic acid and, therefore, does not distinguish between viable, disease-related organisms and nucleic acid persisting from prior or treated infection. Test results should be correlated with patient symptoms and clinical presentation before a definitive diagnosis is made.
During test verification, 32 culture isolates of Candida auris, previously identified using the Bruker matrix-assisted laser desorption/ionization time-of-flight mass spectrometer, were tested, and all 32 positively identified as Candida auris by this polymerase chain reaction (PCR) assay.
Verification studies indicated that the limit of detection (LOD) for C auris spiked onto E-swabs was 37 colony-forming units (CFU)/20 mcL reaction. To evaluate the accuracy of the assay, 30 swabs were spiked with C auris at 1 log above the LOD and 28/30 were positive for E-swabs (93%) by the PCR assay. A panel of 86 surveillance groin/axilla swabs collected from patients meeting the Centers for Disease Control and Prevention screening criteria was tested and was 100% concordant (85 negative, 1 inhibited) with a second PCR surveillance assay performed by the Minnesota Department of Health.
A specificity panel consisting of 78 common skin flora organisms or pathogens (bacteria, yeast, molds, viruses, and parasites) and all were negative by the PCR assay. No positivity was found with any other species of Candida including the closely related Candida duobushaemulonii and Candida haemulonii.
1. Spivak ES, Hanson KE. Candida auris: an emerging fungal pathogen. J Clin Microbiol. 2018;56(2):e01588-17
2. Centers for Disease Control and Prevention (CDC) National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Division of Foodborne, Waterborne, and Environmental Diseases (DFWED): Candida auris. CDC; Updated July 31, 2023. Accessed September 22, 2023. Available at: www.cdc.gov/fungal/candida-auris/index.html
3. Navalkele BD, Revankar S, Chandrasekar P. Candida auris: a worrisome, globally emerging pathogen. Expert Rev Anti Infect Ther. 2017;15(9):819-827
Swabs are processed by placing 50 mcL of the Amies transport medium from an ESwab into neutralization buffer. DNA is extracted.
The extracted DNA is placed on the LightCycler 480 instrument, which amplifies and monitors by fluorescence the development of target nucleotide sequences after each polymerase chain reaction (PCR) cycle. A specific 269 base pairs target sequence from a portion of the 28S rDNA gene from Candida auris is amplified and the resulting segment is detected by melt-curve analysis using sequence-specific fluorescence resonance energy transfer hybridization probes. (Walchak RC, Buckwalter SP, Zinsmaster NM, et al. Candida auris direct detection from surveillance swabs, blood, and urine using a laboratory-developed PCR method. J Fungi (Basel). 2020;6(4):224. doi:10.3390/jof6040224)
Monday through Sunday
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
87481
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
CAURS | Candida auris Surveillance, PCR | 95765-4 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
SRCSR | Specimen Source | 31208-2 |
SCAR | C auris PCR, Result | 95765-4 |