Early identification of microorganisms in blood culture prior to the detection of a positive signal in the BACTEC FX system using matrix-assisted laser desorption/ionization-time of flight mass spectrometry

Ming Cheng Wang, Wei Hung Lin, Jing Jou Yan, Hsin Yi Fang, Te Hui Kuo, Chin Chung Tseng, Jiunn Jong Wu

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17 Citations (Scopus)

Abstract

Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) is a valuable method for rapid identification of blood stream infection (BSI) pathogens. Integration of MALDI-TOF MS and blood culture system can speed the identification of causative BSI microorganisms. Materials and methods: We investigated the minimal microorganism concentrations of common BSI pathogens required for positive blood culture using BACTEC FX and for positive identification using MALDI-TOF MS. The time to detection with positive BACTEC FX and minimal incubation time with positive MALDI-TOF MS identification were determined for earlier identification of common BSI pathogens. Results: The minimal microorganism concentrations required for positive blood culture using BACTEC FX were >107-108 colony forming units/mL for most of the BSI pathogens. The minimal microorganism concentrations required for identification using MALDI-TOF MS were > 107 colony forming units/mL. Using simulated BSI models, one can obtain enough bacterial concentration from blood culture bottles for successful identification of five common Gram-positive and Gram-negative bacteria using MALDI-TOF MS 1.7-2.3 hours earlier than the usual time to detection in blood culture systems. Conclusion: This study provides an approach to earlier identification of BSI pathogens prior to the detection of a positive signal in the blood culture system using MALDI-TOF MS, compared to current methods. It can speed the time for identification of BSI pathogens and may have benefits of earlier therapy choice and on patient outcome.

Original languageEnglish
Pages (from-to)419-424
Number of pages6
JournalJournal of Microbiology, Immunology and Infection
Volume48
Issue number4
DOIs
Publication statusPublished - 2015 Aug 1

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All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Immunology and Microbiology(all)
  • Microbiology (medical)
  • Infectious Diseases

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