Evaluation of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry-Based VITEK MS System for the Identification of Acinetobacter Species from Blood Cultures: Comparison with VITEK 2 and MicroScan Systems.
- Author:
Seung Yeob LEE
1
;
Jong Hee SHIN
;
Soo Hyun KIM
;
Myung Geun SHIN
;
Soon Pal SUH
;
Dong Wook RYANG
Author Information
- Publication Type:Comparative Study ; Evaluation Studies ; Original Article
- Keywords: VITEK MS; VITEK 2; MicroScan; Acinetobacter; Identification
- MeSH: Acinetobacter/*genetics/isolation & purification; Acinetobacter Infections/diagnosis/microbiology; Bacterial Proteins/genetics; Bacterial Typing Techniques/*instrumentation/*methods; Blood/*microbiology; DNA, Bacterial/*analysis/metabolism; Databases, Genetic; Humans; *Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- From:Annals of Laboratory Medicine 2015;35(1):62-68
- CountryRepublic of Korea
- Language:English
- Abstract: BACKGROUND: Acinetobacter species are the leading cause of bloodstream infection (BSI), but their correct identification is challenging. We evaluated the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based VITEK MS (bioMerieux, France), and two automated systems, VITEK 2 (bioMerieux) and MicroScan (Siemens, USA) for identification of Acinetobacter BSI isolates. METHODS: A total of 187 BSI isolates recovered at a university hospital in Korea between 2010 and 2012 were analyzed. The identification results obtained using VITEK MS and two automated systems were compared with those of rpoB sequencing. RESULTS: Of 187 isolates analyzed, 176 were identified to the species level by rpoB sequencing: the Acinetobacter baumannii group (ABG; 101 A. baumannii, 43 A. nosocomialis, 10 A. pittii isolates) was most commonly identified (82.4%), followed by Acinetobacter genomic species 13BJ/14TU (5.3%), A. ursingii (2.1%), A. soli (2.1%), A. bereziniae (1.1%), and A. junii (1.1%). Correct identification rates to the species group (ABG) level or the species level was comparable among the three systems (VITEK MS, 90.3%; VITEK 2, 89.2%; MicroScan, 86.9%). However, VITEK MS generated fewer misidentifications (0.6%) than VITEK 2 (10.8%) and MicroScan (13.1%) (P<0.001). In addition, VITEK MS demonstrated higher specificity (100%) for discrimination between ABG and non-ABG isolates than the other systems (both, 31.8%) (P<0.001). CONCLUSIONS: The VITEK MS system is superior to the VITEK 2 and MicroScan systems for identification of Acinetobacter BSI isolates, with fewer misidentifications and better discrimination between the ABG and non-ABG isolates.
