title: Rapid identification of environmental bacterial strains by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.
abstract: In recent years, various mass spectrometry procedures have been developed for bacterial identification. The accuracy and speed with which data can be obtained by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) could make this a powerful tool for environmental monitoring. However, minor variations in the sample preparation can influence the mass spectra significantly. Therefore, the first objectives of this study were the adjustment and the optimization of experimental parameters allowing a rapid identification of whole bacterial cells without laborious sample preparation. The tested experimental parameters were matrix, extraction solvent, salt content, deposition method, culture medium and incubation time. This standardized protocol was applied to identify reference and environmental bacterial strains of Escherichia coli, Salmonella and Acinetobacter. The environmental bacterial strains were isolated from sewage sludge using an original microextraction procedure based on repeated sonications and enzymatic treatments. The bacterial identification was realized by the observation of the respective genus-, species- and strain-specific biomarkers. This bacterial taxonomy could be completed within one hour, with minimal sample preparation, provided that sufficient bacteria had been collected prior to MALDI-TOF analysis.
authors.affiliation: Mass Spectrometry Laboratory, University of Liège, B-4000 Liège, Belgium. v.ruelle@ulg.ac.be
authors.forename: Virginie
authors.initials: V
authors.lastname: Ruelle
authors.forename: Benaissa
authors.initials: B
authors.lastname: El Moualij
authors.forename: Willy
authors.initials: W
authors.lastname: Zorzi
authors.forename: Philippe
authors.initials: P
authors.lastname: Ledent
authors.forename: Edwin De
authors.initials: ED
authors.lastname: Pauw
mesh_terms: D039903:Actinobacteria / Q000145:classification / Q000166:cytology / Q000302:isolation & purification; D001419:Bacteria / Q000145:classification* / Q000166:cytology / Q000302:isolation & purification*; D018929:Cell Culture Techniques / Q000379:methods; D002469:Cell Separation / Q000379:methods*; D002470:Cell Survival; D015169:Colony Count, Microbial / Q000379:methods; D004784:Environmental Monitoring / Q000379:methods; D004785:Environmental Pollutants / Q000302:isolation & purification*; D004926:Escherichia coli / Q000145:classification / Q000166:cytology / Q000302:isolation & purification; D012475:Salmonella / Q000145:classification / Q000166:cytology / Q000302:isolation & purification; D012722:Sewage / Q000032:analysis* / Q000382:microbiology*; D013045:Species Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D004785:Environmental Pollutants; D012722:Sewage