Comparison of the Bruker MALDI-TOF mass spectrometry system and conventional phenotypic methods for identification of Gram-positive rods

PLoS One. 2014 Sep 3;9(9):e106303. doi: 10.1371/journal.pone.0106303. eCollection 2014.

Abstract

In recent years, MALDI-TOF Mass Spectrometry (MS) method has emerged as a promising and a reliable tool for bacteria identification. In this study we compared Bruker MALDI-TOF MS and conventional phenotypic methods to identify a collection of 333 Gram-positive clinical isolates comprising 22 genera and 60 species. 16S rRNA sequencing was the reference molecular technique, and rpoB gene sequecing was used as a secondary gene target when 16Sr RNA did not allow species identification of Corynebacterium spp. We also investigate if score cut-offs values of ≥ 1,5 and ≥ 1,7 were accurate for genus and species-level identification using the Bruker system. Identification at species level was obtained for 92,49% of Gram-positive rods by MALDI-TOF MS compared to 85,89% by phenotypic method. Our data validates the score ≥ 1,5 for genus level and ≥ 1,7 for species-level identification in a large and diverse collection of Gram-positive rods. The present study has proved the accuracy of MALDI-TOF MS as an identification method in Gram-positive rods compared to currently used methods in routine laboratories.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Typing Techniques
  • DNA, Bacterial / genetics
  • Gram-Positive Bacteria / classification
  • Gram-Positive Bacteria / genetics
  • Gram-Positive Bacteria / isolation & purification*
  • Humans
  • RNA, Ribosomal, 16S / genetics*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods*

Substances

  • DNA, Bacterial
  • RNA, Ribosomal, 16S

Grants and funding

This work was supported by grants from the Secretaría de Ciencia y Técnica de la Universidad de Buenos Aires (UBACyT) to C.V. M.S.R. is a member of the CONICET research career. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.