Rapid Analysis of Bacteremia by Membrane Extraction Electrospray Ionization Mass Spectrometry
Abstract A custom membrane extraction electrospray ionization mass spectrometry (MEESI-MS) method was developed to detect the representative bacteric metabolites and classify four kinds of bacteria including Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa. The chemical fingerprints of each bacterium were obtained using this MEESI-MS. Principal component analysis (PCA) was then applied to analyze the information from the obtained fingerprint spectra and classify the samples. The results showed that MEESI-MS was capable of rapidly obtaining metabolic fingerprints of blood samples and direct identifying the representative metabolites from each bacterium via employing both accurate mass measurements and structural information from tandem mass spectra. The overall analysis time was less than 65 min (including a culture time of about 60 min). This method was featured by the simplicity in sample pretreatment, ionization activation and data analysis and was promising in rapid identification of bacterial species in clinical bacteremia and septicemia.