Evaluation of Bruker Biotyper and Vitek MS for the identification of Candida tropicalis on different solid culture media

• Main Authors: He Wang, Ying Li, Xin Fan, Tzong-Shi Chiueh, Ying-Chun Xu, Po-Ren Hsueh
• Format: Article
• Language: English
• Published: Elsevier 2019-08-01
• Series: Journal of Microbiology, Immunology and Infection
• Online Access: http://www.sciencedirect.com/science/article/pii/S1684118217302396

Background: The aim of this study was to investigate the performance of the Bruker Biotyper matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and Vitek MS systems for identification of genetically-confirmed blood isolates of Candida tropicalis that had been grown on several types of culture media commonly used for primary fungal isolation. Methods: Isolates included 105 from the National China Hospital Invasive Fungal Surveillance Net program (CHIF-NET) and 120 from National Taiwan University Hospital (NTUH). Culture media tested for CHIF-NET isolates included trypticase soy agar supplemented with 5% sheep blood (BAP), Sabouraud dextrose agar (SDA-C), CHROMagar, China blue agar (CBA), chocolate agar supplemented with vancomycin (CAP-VA), and MacConkey agar (MAC). Culture media used for NTUH isolates included BAP, SDA, CHROMagar, eosin methylene blue (EMB), inhibitory mold agar (IMA), Mycosel agar, and cornmeal agar (CMA). Results: The Bruker Biotyper correctly identified all CHIF-NET isolates to the species level on all six agar media tested and correctly identified the majority of NTUH isolates with the exception of isolates grown on SDA (85.8%) and CMA (52.5%). The Vitek MS system correctly identified all CHIF-NET isolates to the species level with the exception of isolates grown on CHROMagar (84.8%), and correctly identified the majority of NTUH isolates with the exception of isolates grown on SDA (51.7%), Mycosel agar (57.5%), and CMA (9.2%) for NTUH isolates. Conclusion: Clinical microbiologists should be aware that different culture media can affect the performance of the Bruker Biotyper MALDI-TOF MS and Vitek MS systems in identifying C. tropicalis. Keywords: Candida tropicalis, MALDI-TOF MS, Bruker Biotyper, Vitek MS, Culture media