Candida auris PCR: A Molecular Diagnostic Test for Detection of an Emerging Pathogen
Candida auris PCR is a molecular diagnostic test that uses polymerase chain reaction technology to specifically identify the emerging multidrug-resistant fungal pathogen Candida auris, providing more rapid and accurate identification than conventional culture-based methods. 1, 2
Overview of Candida auris PCR
PCR-based detection methods for C. auris target unique genetic sequences specific to this organism, such as the internal transcribed spacer (ITS) region or GPI protein-encoding genes, allowing for reliable differentiation from other Candida species 1, 3
C. auris is commonly misidentified by conventional phenotypic identification platforms, making molecular methods particularly valuable for accurate diagnosis 2
These molecular assays overcome the deficiencies of existing phenotypic tests in identifying C. auris and related species with 100% concordance with DNA sequencing results 2
Clinical Applications and Benefits
C. auris PCR is particularly valuable for infection control screening in healthcare settings, where rapid identification is crucial to prevent outbreaks 4, 3
The test can be used for surveillance swabs from multiple body sites (groin, axilla, nose, throat, rectum) to detect colonization in high-risk patients 3
PCR methods can detect C. auris directly from various clinical specimens including surveillance swabs, blood, and urine 5
Molecular detection is safer than culture-based methods, as sample preparation steps can render C. auris non-viable, reducing the risk of laboratory contamination 4
Technical Aspects
C. auris-specific PCR assays typically have high analytical sensitivity, with limits of detection as low as 1-4 colony forming units per reaction 4, 3
Some PCR assays can differentiate C. auris from closely related species (C. duobushaemulonii, C. haemulonii, C. pseudohaemulonii) based on melting curve analysis 5
For enhanced reliability, some protocols employ multiple primer pairs targeting different genetic regions, which increases robustness and reduces the risk of false negatives 1
Current Limitations
Despite the high sensitivity and specificity of PCR methods for C. auris detection, the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) guidelines note that molecular detection techniques for Candida species generally lack external validation and standardization 6
According to ESCMID guidelines, third-party appraisal of results and harmonization of PCR-based techniques should be completed before definitive recommendations can be made regarding clinical utility 6
While in-house PCR techniques for Candida detection have shown pooled sensitivity and specificity over 85% in meta-analyses, the variability in materials and methods used across different laboratories remains a challenge 6
Implementation in Clinical Practice
PCR screening for C. auris is particularly valuable for patients with risk factors, such as recent hospitalization in facilities with known C. auris cases or in countries with documented outbreaks 3
The rapid turnaround time of PCR (hours versus days for culture) allows for faster implementation of infection control measures when positive cases are identified 4, 5
Some institutions have implemented C. auris PCR as part of admission screening protocols for high-risk patients, with positive detection rates around 4% in targeted populations 3