title: Comparison of Vitek Matrix-assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Versus Conventional Methods in Candida Identification.
abstract: Candida species are generally identified by conventional methods such as germ tube or morphological appearance on corn meal agar, biochemical methods using API kits and molecular biological methods. Alternative to these methods, rapid and accurate identification methods of microorganisms called matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDİ-TOF MS) has recently been described. In this study, Candida identification results by API Candida kit, API 20C AUX kit and identifications on corn meal agar (CMA) are compared with the results obtained on Vitek-MS. All results were confirmed by sequencing internal transcribed spacer (ITS) regions of rDNA. Totally, 97 Candida strains were identified by germ tube test, CMA, API and Vitek-MS. Vitek-MS results were compatible with 74.2 % of API 20C AUX and 81.4 % of CMA results. The difference between the results of API Candida and API 20C AUX was detected. The ratio of discrepancy between Vitek-MS and API 20C AUX was 25.8 %. Candida species mostly identified as C. famata or C. tropicalis by and not compatible with API kits were identified as C. albicans by Vitek-MS. Sixteen Candida species having discrepant results with Vitek-MS, API or CMA were randomly chosen, and ITS sequence analysis was performed. The results of sequencing were compatible 56.2 % with API 20C AUX, 50 % with CMA and 93.7 % with Vitek-MS. When compared with conventional identification methods, MS results are more reliable and rapid for Candida identification. MS system may be used as routine identification method in clinical microbiology laboratories.
authors.affiliation: Department of Medıcal Mıcrobıology, Kocaelı Unıversıty Hospıtal, Kocaelı, Turkey. sema.keceli@yahoo.com.tr.
authors.forename: Sema Aşkın
authors.initials: SA
authors.lastname: Keçeli
authors.affiliation: Department of Medıcal Mıcrobıology, Kocaelı Unıversıty Hospıtal, Kocaelı, Turkey.
authors.forename: Devrim
authors.initials: D
authors.lastname: Dündar
authors.affiliation: Department of Medıcal Mıcrobıology, Kocaelı Unıversıty Hospıtal, Kocaelı, Turkey.
authors.forename: Gülden Sönmez
authors.initials: GS
authors.lastname: Tamer
mesh_terms: D002175:Candida / Q000145:classification* / Q000302:isolation & purification*; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D008828:Microbiological Techniques / Q000379:methods*; D017422:Sequence Analysis, DNA; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013997:Time Factors
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer
keywords: Candida; Identification methods; MALDI–TOF