[Establishment of a recombined mannose-binding lectin protein-magnetic beads-enriched binding recombinant enzyme-assisted polymerase chain reaction assay for Candida in blood samples].

Objective

To establish a nested recombinant enzyme-assisted polymerase chain reaction (RAP) technique combined with recombined mannose-binding lectin protein (M1 protein)-magnetic beads enrichment for the detection of Candida albicans (C. albicans) and Candida tropicalis (C. tropicalis) in blood samples for the early diagnosis of candidemia albicans and candidiemia tropicalis.

Methods

The primer probes for highly conserved regions of the internal transcribed spacerregions of C. albicans and C. tropicalis were deigned to establish RAP assays for the detections of C. albicans and C. tropicalis; The sensitivity and reproducibility of nucleic acid tests with gradient dilutions of standard strains and specificity of nucleic acid tests with common clinical pathogens causing bloodstream infection were condcuted. M1 protein-magnetic bead enriched plasma C. albicans and C. tropicalis were used for RAP and PCR in with simulated samples and the results were compared.

Results

The sensitivity of the established dual RAP assay was 2.4-2.8 copies/reaction, with higher reproducibility and specificity. M1 protein-magnetic bead enrichment of pathogen combined with the dual RAP assay could complete the detections of C. albicans and C. tropicalis in plasma within 4 hours. Fie the pathogen samples at concentration <10 CFU/ml, the number of the samples tested by RAP was higher than that tested by PCR after enrichment.

Conclusion

In this study, a dual RAP assay for the detections of C. albicans and C. tropicalis in blood sample was developed, which has the advantages of accuracy, rapidity, and less contaminants and has great potential for rapid detection of Candidemia.