Rapid identification and antimicrobial susceptibility testing of positive blood cultures using MALDI-TOF MS and a modification of the standardised disc diffusion test: a pilot study.
AffiliationMicrobiology Laboratory, University Hospital Waterford, Waterford, Ireland.
MetadataShow full item record
CitationRapid identification and antimicrobial susceptibility testing of positive blood cultures using MALDI-TOF MS and a modification of the standardised disc diffusion test: a pilot study. 2016 J. Clin. Pathol.
JournalJournal of clinical pathology
AbstractIn an era when clinical microbiology laboratories are under increasing financial pressure, there is a need for inexpensive, yet effective, rapid microbiology tests. The aim of this study was to evaluate a novel modification of standard methodology for the identification and antimicrobial susceptibility testing (AST) of pathogens in positive blood cultures, reducing the turnaround time of laboratory results by 24 h.
277 positive blood cultures had a Gram stain performed and were subcultured and incubated at 37°C in a CO2 atmosphere for 4-6 h. Identification of the visible growth was performed using matrix-assisted laser desorption time of flight mass spectrometry (MALDI-TOF MS). Taking a modified approach to the Clinical and Laboratory Standards Institute-standardised AST methodology, an inoculum density of 0.5 McFarland was prepared from the early growth for disc diffusion testing. The standard AST method was also performed on the 18-24 h culture.
96% (n=73/76) of gram-negative organisms were correctly identified by MALDI-TOF MS. Comparative analysis of the rapid and standard AST results showed an overall interpretive category error rate of 7.7% (6.7% minor errors, 0.6% major errors and 0.4% very major errors). 100% of Staphylococcus aureus (n=41) and enterococcus isolates (n=9) were correctly identified after 4-6 h incubation. The overall AST categorical agreement was also 100% for these isolates.
An incubation of 4-6 h directly from positive blood cultures allowed for both a rapid species identification and an antimicrobial susceptibility result approximately 24 h earlier than is possible using standard methodology.
- MALDI-TOF mass spectrometry following short incubation on a solid medium is a valuable tool for rapid pathogen identification from positive blood cultures.
- Authors: Kohlmann R, Hoffmann A, Geis G, Gatermann S
- Issue date: 2015 Jun-Aug
- [Identification of staphylococci directly from positive blood culture bottles by MALDI-TOF MS system].
- Authors: Kilic A, Baysallar M
- Issue date: 2014 Jul
- Rapid Identification and Antimicrobial Susceptibility Testing for Urinary Tract Pathogens by Direct Analysis of Urine Samples Using a MALDI-TOF MS-Based Combined Protocol.
- Authors: Li W, Sun E, Wang Y, Pan H, Zhang Y, Li Y, Zhang X, Li C, Du L, Wang C
- Issue date: 2019
- Identification and susceptibility testing of microorganism by direct inoculation from positive blood culture bottles by combining MALDI-TOF and Vitek-2 Compact is rapid and effective.
- Authors: Romero-Gómez MP, Gómez-Gil R, Paño-Pardo JR, Mingorance J
- Issue date: 2012 Dec
- Rapid identification of microorganisms from positive blood cultures by MALDI-TOF mass spectrometry subsequent to very short-term incubation on solid medium.
- Authors: Idelevich EA, Schüle I, Grünastel B, Wüllenweber J, Peters G, Becker K
- Issue date: 2014 Oct