Advantages and Accuracy of Multiprobe Real-Time PCR Detection of Uncommon and Mixed Candida Species in Blood Culture Broth of Candidemic Patients

Abstract

Candidemia is a fatal condition and usually caused by a single common Candida species. Mixed Candida blood stream infection is not common, but it has a higher morbidity and mortality. This study reported the advantages of multiprobe real-time PCR assay to identify uncommon and mixed Candida species in blood culture broth which were misidentified by phenotypic methods. The assay shows a perfect specificity for identification of 137 individual yeast positive blood culture samples. Eleven of these (8%) were misidentified by the routine methods. There were two samples of Candida albicans, C. glabrata and C. glabrata, C. tropicalis mixed infections that were detected by the real-time PCR assay. The other nine samples such as 2 C. parapsilosis, 2 C. glabrata, 2 C. athensensis, 1 C. dublinensis, 1 C. aquaetextoris and 1 C. haemulonis show discordant results between real-time PCR and phenotype, whereas DNA sequencing confirmed the accuracy of the real-time PCR results. The advantages of the real-time PCR assay over traditional mycology make it valuable for use in a routine clinical setting.