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Comparative Study
. 2011 Jul;57(7):1057-67.
doi: 10.1373/clinchem.2011.161968. Epub 2011 May 16.

Comparative analysis of PCR-electrospray ionization/mass spectrometry (MS) and MALDI-TOF/MS for the identification of bacteria and yeast from positive blood culture bottles

Erin J Kaleta  1 , Andrew E Clark, Abdessalam Cherkaoui, Vicki H Wysocki, Elizabeth L Ingram, Jacques Schrenzel, Donna M Wolk
Affiliations
Comparative Study

Comparative analysis of PCR-electrospray ionization/mass spectrometry (MS) and MALDI-TOF/MS for the identification of bacteria and yeast from positive blood culture bottles

Erin J Kaleta et al. Clin Chem. 2011 Jul.

Abstract

Background: Emerging technologies for rapid identification of microbes demonstrate a shift from traditional biochemical and molecular testing algorithms toward methods using mass spectrometry (MS) for the semiquantitative analysis of microbial proteins and genetic elements. This study was performed to assess the diagnostic accuracy of 2 such technologies, PCR-electrospray ionization (ESI)/MS and MALDI-TOF/MS, with respect to phenotypic and biochemical profiling as a reference standard method. A positive challenge set of blood culture bottles was used to compare PCR-ESI/MS and MALDI-TOF/MS performance on a matched set of samples.

Methods: We performed characterization of bloodstream infections from blood cultures using the Ibis T5000 PCR-ESI/MS and the Bruker MALDI Biotyper 2.0 (MALDI-TOF/MS) platforms for microbial identification. Diagnostic accuracy was determined by independent comparison of each method to phenotypic and biochemical characterization with Vitek2 analysis as the reference standard identification.

Results: The diagnostic accuracy, represented as positive agreement, at the genus level was 0.965 (0.930-0.984) for PCR-ESI/MS and 0.969 (0.935-0.987) for MALDI-TOF/MS, and at the species level was 0.952 (0.912-0.974) with PCR-ESI/MS and 0.943 (0.902-0.968) for MALDI-TOF/MS. No statistically significant difference was found between PCR-ESI/MS and MALDI-TOF/MS in the ability to rapidly identify microorganisms isolated from blood culture.

Conclusions: Our results demonstrate that PCR-ESI/MS and MALDI-TOF/MS are equivalent in their ability to characterize bloodstream infections with respect to the reference standard, and highlight key differences in the methods that allow for each method to have a unique niche as a tool for rapid identification of microbes in blood cultures.

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Figures

Fig. 1.
Fig. 1.. Flow chart for this study.
All selected blood culture bottles were evaluated by each index test and the reference standard, with no exclusions.
Fig. 2.
Fig. 2.. Concordance seen with respect to the reference standard.
(A), PCR-ESI/MS identification on the genus level. FN, false negative; FP, false positive. (B), PCR-ESI/MS identification on the species level. (C), MALDI-TOF/MS identification on the genus level. (D), MALDI-TOF/MS identification on the species level.
See this image and copyright information in PMC

References

    1. Chen JR, Lee SY, Yang BH, Lu JJ. Rapid identification and susceptibility testing using the VITEK 2 system using culture fluids from positive BacT/ALERT blood cultures. J Microbiol Immunol Infect 2008;41:259–64. - PubMed
    1. Ling TK, Liu ZK, Cheng AF. Evaluation of the VITEK 2 system for rapid direct identification and susceptibility testing of gram-negative bacilli from positive blood cultures. J Clin Microbiol 2003;41:4705–7. - PMC - PubMed
    1. Raja S, Ching J, Xi L, Hughes SJ, Chang R, Wong W et al. Technology for automated, rapid, and quantitative PCR or reverse transcription-PCR clinical testing. Clin Chem 2005;51:882–90. - PubMed
    1. Wolk DM, Struelens MJ, Pancholi P, Davis T, Della-Latta P, Fuller D et al. Rapid detection of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in wound specimens and blood cultures: multicenter preclinical evaluation of the Cepheid Xpert MRSA/SA skin and soft tissue and blood culture assays. J Clin Microbiol 2009;47:823–6. - PMC - PubMed
    1. Forrest GN, Mankes K, Jabra-Rizk MA, Weekes E, Johnson JK, Lincalis DP, Venezia RA. Peptide nucleic acid fluorescence in situ hybridization-based identification of Candida albicans and its impact on mortality and antifungal therapy costs. J Clin Microbiol 2006;44:3381–3. - PMC - PubMed

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