Integration of microfiltration and anion-exchange nanoparticles-based magnetic separation with MALDI mass spectrometry for bacterial analysis.
Matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) is powerful in characterizing and identifying bacterial isolates. However, sufficient quantities of bacterial cells are required for generating MALDI mass spectra and a procedure to isolate and enrich target bacteria from sample matrix prior to MALDI-MS analysis is often necessary. In this paper, anion-exchange superparamagnetic nanoparticles (NPs), i.e., fluidMAG-DEAE and fluidMAG-Q, were employed to capture Aeromonas, Salmonella, Pseudomonas, Enterococcus, Bacillus, Staphylococcus and Escherichia coli from aqueous solutions and fresh water. The magnetically isolated bacteria were then characterized by whole cell MALDI-MS. The capture efficiency was found to be dependent on bacterial species, medium pH, the functional group and concentration of the NPs. The experimental results demonstrated that fluidMAG-DEAE and fluidMAG-Q were broad spectrum probes for bacteria. Furthermore, both dead and live bacteria could be captured by the NPs, and the live bacteria captured remained viable. Membrane filtration prior to the magnetic isolation could increase enrichment factor and eliminate potential matrix interference. A detection limit of 1 x 10(3)cfu/ml was achieved for the bacteria spiked in tap water and reservoir water, and the analytical time was around 2h.
Center for Advanced Water Technology, Public Utilities Board, WaterHub, Singapore 608576, Singapore.
Shuping
S
Li
Zhongxian
Z
Guo
Ying
Y
Liu
Zhaoguang
Z
Yang
Hui Kim
HK
Hui
D016980:Aeromonas hydrophila / Q000302:isolation & purification / Q000648:ultrastructure; D000837:Anion Exchange Resins / Q000737:chemistry; D001412:Bacillus subtilis / Q000302:isolation & purification / Q000648:ultrastructure; D001419:Bacteria / Q000302:isolation & purification* / Q000648:ultrastructure; D016983:Enterococcus / Q000302:isolation & purification / Q000648:ultrastructure; D004926:Escherichia coli / Q000302:isolation & purification / Q000648:ultrastructure; D005374:Filtration; D005618:Fresh Water / Q000382:microbiology; D006801:Humans; D008280:Magnetics; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry*; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification / Q000648:ultrastructure; D015203:Reproducibility of Results; D019779:Salmonella enterica / Q000302:isolation & purification / Q000648:ultrastructure; D013045:Species Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation / Q000379:methods*; D013211:Staphylococcus aureus / Q000302:isolation & purification / Q000648:ultrastructure; D014556:Urine / Q000382:microbiology; D014871:Water Microbiology
D000837:Anion Exchange Resins