Ann Lab Med.  2015 Jan;35(1):69-75. 10.3343/alm.2015.35.1.69.

Evaluation of VITEK Mass Spectrometry (MS), a Matrix-Assisted Laser Desorption Ionization Time-of-Flight MS System for Identification of Anaerobic Bacteria

• Lee W
• Kim M
• Yong D
• Jeong SH
• Lee K
• Chong Y

• KMID: 2363150
• DOI: http://doi.org/10.3343/alm.2015.35.1.69

Abstract

BACKGROUND
By conventional methods, the identification of anaerobic bacteria is more time consuming and requires more expertise than the identification of aerobic bacteria. Although the matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems are relatively less studied, they have been reported to be a promising method for the identification of anaerobes. We evaluated the performance of the VITEK MS in vitro diagnostic (IVD; 1.1 database; bioMerieux, France) in the identification of anaerobes.
METHODS
We used 274 anaerobic bacteria isolated from various clinical specimens. The results for the identification of the bacteria by VITEK MS were compared to those obtained by phenotypic methods and 16S rRNA gene sequencing.
RESULTS
Among the 249 isolates included in the IVD database, the VITEK MS correctly identified 209 (83.9%) isolates to the species level and an additional 18 (7.2%) at the genus level. In particular, the VITEK MS correctly identified clinically relevant and frequently isolated anaerobic bacteria to the species level. The remaining 22 isolates (8.8%) were either not identified or misidentified. The VITEK MS could not identify the 25 isolates absent from the IVD database to the species level.
CONCLUSIONS
The VITEK MS showed reliable identifications for clinically relevant anaerobic bacteria.

Keyword

MALDI-TOF MS; VITEK MS; Anaerobic bacteria

MeSH Terms

Bacteria, Anaerobic/*genetics/isolation & purification
Bacterial Typing Techniques/*instrumentation/*methods
Body Fluids/microbiology
Databases, Genetic
Humans
RNA, Ribosomal, 16S/*analysis/metabolism
Sequence Analysis, DNA
*Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
RNA, Ribosomal, 16S

Reference

1. Murphy EC. Gram-positive anaerobic cocci-commensals and opportunistic pathogens. FEMS Microbiol Rev. 2013; 37:520–553. PMID: 23030831.

2. Nagy E. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry: a new possibility for the identification and typing of anaerobic bacteria. Future Microbiol. 2014; 9:217–233. PMID: 24571074.

3. Wieser A, Schneider L, Jung J, Schubert S. MALDI-TOF MS in microbiological diagnostics-identification of microorganisms and beyond (mini review). Appl Microbiol Biotechnol. 2012; 93:965–974. PMID: 22198716.

4. Marko DC, Saffert RT, Cunningham SA, Hyman J, Walsh J, Arbefeville S, et al. Evaluation of the Bruker Biotyper and Vitek MS matrix-assisted laser desorption ionization-time of flight mass spectrometry systems for identification of nonfermenting gram-negative bacilli isolated from cultures from cystic fibrosis patients. J Clin Microbiol. 2012; 50:2034–2039. PMID: 22495566.

5. Culebras E, Rodríguez-Avial I, Betriu C, Gómez M, Picazo JJ. Rapid identification of clinical isolates of Bacteroides species by matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry. Anaerobe. 2012; 18:163–165. PMID: 21963387.

6. Fedorko DP, Drake SK, Stock F, Murray PR. Identification of clinical isolates of anaerobic bacteria using matrix-assisted laser desorption ionization-time of flight mass spectrometry. Eur J Clin Microbiol Infect Dis. 2012; 31:2257–2262. PMID: 22371295.

7. La Scola B, Fournier PE, Raoult D. Burden of emerging anaerobes in the MALDI-TOF and 16S rRNA gene sequencing era. Anaerobe. 2011; 17:106–112. PMID: 21672636.

8. Nagy E, Becker S, Kostrzewa M, Barta N, Urbán E. The value of MALDI-TOF MS for the identification of clinically relevant anaerobic bacteria in routine laboratories. J Med Microbiol. 2012; 61:1393–1400. PMID: 22700545.

9. Jamal WY, Shahin M, Rotimi VO. Comparison of two matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry methods and API 20AN for identification of clinically relevant anaerobic bacteria. J Med Microbiol. 2013; 62:540–544. PMID: 23242640.

10. Dubois D, Grare M, Prere MF, Segonds C, Marty N, Oswald E. Performances of the Vitek MS matrix-assisted laser desorption ionization-time of flight mass spectrometry system for rapid identification of bacteria in routine clinical microbiology. J Clin Microbiol. 2012; 50:2568–2576. PMID: 22593596.

11. Clark AE, Kaleta EJ, Arora A, Wolk DM. Matrix-assisted laser desorption ionization-time of flight mass spectrometry: a fundamental shift in the routine practice of clinical microbiology. Clin Microbiol Rev. 2013; 26:547–603. PMID: 23824373.

12. Chun J, Lee JH, Jung Y, Kim M, Kim S, Kim BK, et al. EzTaxon: a web-based tool for the identification of prokaryotes based on 16S ribosomal RNA gene sequences. Int J Syst Evol Microbiol. 2007; 57:2259–2261. PMID: 17911292.

13. Clinical and Laboratory Standards Institute. Interpretive criteria for identification of bacteria and fungi by DNA target sequencing. Approved guideline, MM18-A. Wayne, PA: Clinical and Laboratory Standards Institute;2008.

14. Justesen US, Holm A, Knudsen E, Andersen LB, Jensen TG, Kemp M, et al. Species identification of clinical isolates of anaerobic bacteria: a comparison of two matrix-assisted laser desorption ionization-time of flight mass spectrometry systems. J Clin Microbiol. 2011; 49:4314–4318. PMID: 21998433.

15. Martiny D, Busson L, Wybo I, El Haj RA, Dediste A, Vandenberg O. Comparison of the Microflex LT and Vitek MS systems for routine identification of bacteria by matrix-assisted laser desorption ionization-time of flight mass spectrometry. J Clin Microbiol. 2012; 50:1313–1325. PMID: 22322345.

16. Garner O, Mochon A, Branda J, Burnham CA, Bythrow M, Ferraro M, et al. Multi-centre evaluation of mass spectrometric identification of anaerobic bacteria using the VITEK® MS system. Clin Microbiol Infect. 2014; 20:355–359. PMID: 23991748.