MALDI-TOF MS as a universal tool for the characterisation of pathogenic bacteria – A comparative analysis of MALDI-TOF MS spectral fingerprints over a six-year period

Abstract number: P1995

Dare D., Sutton H., Shah H.

Objective: There has been a significant increase in the number of papers demonstrating MALDI-TOF MS as a powerful, rapid, high throughput technique for the characterisation of pathogenic organisms. These isolate are generally characterised against a limited database built in house with the experimentation carried out in relatively quick succession, on the same sample set and same instrumentation by the same operator. In the majority of these cases identification is based upon a small number of exclusive peaks associated with each species, since variability is often observed in the spectral pattern. This paper examines this variability and hence the ability of the technique for use as a universal tool.

Method: Six strains, Bacteroides fragilis, Pseudomonas aeruginosa, Escherichia coli, Corynebacterium jeikium, Vibrio parahaemolyticus and Micrococcus lylae were analysed by MALDI-TOF MS repeatedly over a period of 6 years. The resulting spectral fingerprints were derived from isolates cultured from different freeze dried ampoules; media; reagent stocks; instrumentation and technical personnel. The resulting spectra patterns were compared for reproducibility and the effects upon identification against an extensive MALDI-TOF MS database of over 5000 spectral entries, covering more than 600 different species examined.

Results: The results demonstrate the spectral fingerprints are very robust, with variations generally observed in the peak intensity of the mass patterns. Furthermore the differences observed were insufficient to cause misidentification of the spectral fingerprint against a substantial database.

Conclusion: This extended study therefore validates MALDI-TOF MS as a tool for rapid universal characterisation of bacteria.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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