Reproducibility of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for replicate bacterial culture analysis

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometr y (MALDI-TOFMS) was used to demonstrate the reproducibility of bacterial sp ectra collected on different days. The reproducibility of analysis by MALDI -MS of intact Escherichia coli and Bacillus atrophaeus is presented as a re plicate culture study in which spectra were collected on ten different occa sions over a three-month period and by two different operators. The analysi s resulted in the detection of specific biomarkers in the m/z 2000-20000 ra nge. Some of the peaks in the Escherichia call spectra are identified by co mparison with other published work. All of the spectra obtained are reprodu cible over the course of the experiment, but operator variability does exis t. The Escherichia coli spectra show operator variability while the Bacillu s atrophaeus spectra do not. This work demonstrates the utility of MALDI in obtaining consistent spectra from bacteria over a period of time. Copyrigh t (C) 1999 John Whey & Sons, Ltd.