The performance of a visual slide-based DNA microarray for the identification of non-albicans Candida spp. was evaluated. Among 167 isolates that had previously been identified by Vitek 2, the agreement between DNA microarray and sequencing results was 97.6%. This DNA microarray platform showed excellent performance.
Candida species are the predominant cause of systemic fungal infections in hospitalized patients and represent the fourth most common microorganisms found in blood cultures (1, 2). In a large, laboratory-based study conducted in Brazilian hospitals, the incidence of candidemia was found to be 2.49 cases per 1,000 patient admissions (3), which is higher than that in the United States (0.28/1,000), Europe (0.2/1,000), or France (0.17/1,000) (4-7). In our setting, the reported candidemia incidence was 0.54 cases per 1,000 patient days, with 56% non-albicans Candida spp. (8). An increase in the proportion of non-albicans Candida spp. has been observed worldwide with distinctive patterns of antifungal susceptibility (9, 10).The development of automated microbiology systems has represented a significant improvement in the identification of Candida spp. However, their diagnostic accuracy has been reported to range from 43 to 95% (11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Considering the frequency of occurrence, the high mortality rate, and the susceptibility patterns of non-albicans Candida spp., novel point-of-care molecular technologies are urgently needed in clinical practice. Our study evaluated the ability of a novel plastic slide-based DNA microarray to identify non-albicans Candida spp. isolated from blood cultures.(Partial results of this study were presented at the 18th Congress of the International Society for Human and Animal Mycology, Berlin, Germany, 2012.) A retrospective cohort surveillance study was performed that included 167 non-albicans Candida The novel DNA microarray platform was developed by the Medical Mycology Research Center at Chiba University (MMRCChiba) to identify the following 12 genera and 32 fungal species, including 9 non-albicans Candida spp.: C. guilliermondii, C. lusitaniae, C. krusei, C. glabrata, C. parapsilosis, C. tropicalis, C. dubliniensis, C. famata, C. kefyr, C. albicans For DNA microarray platform fabrication, the oligonucleotide probes used, consisting of 14 to 20 species-specific nucleotide sequences with biotin-labeled poly(T) anchors at the end of each nucleotide (Invitrogen, Showajima, Japan), were designed based on the internal transcribed spacer (ITS) sequences (ITS1 and ITS2) of the type strains (GenBank database, ATCC, Centraalbureau voor Schimmelcultures [CBS], and MMRC-Chiba). Multiple-sequence alignments were performed with the BioEdit software (version 7.1.3; http://www.mbio.ncsu.edu/BioEdit/bioedit .html). Conserved regions were also used as targets for genusspecific probes or as controls. Four to 11 oligonucleotide probe sequences were included for each Candida sp.; six probes were designed for common sequences, and two were designed for biotin l...
