Laser microprobe mass spectrometry of individual bacterial organisms and of isolated bacterial compounds: a tool in microbiology

Abstract Laser microprobe mass spectrometry (LAMMS) of individual bacterial organisms can render information not accessible to conventional microbiological methods, in particular on the distribution of the physiological state within a bacterial population. This information is obtained from the mass spectrometric analysis of a limited number of bacteria via the measurement of their intrabacterial sodium to potassium ratios (Na + ,K + -ratios) and organic fragment ion patterns. In this contribution, the method is briefly reviewed in examples with a cultivable myobacterial species. With the noncultivable Myobacterium l leprae , isolated from patient skin biopsies or infected armadillo tissue, it is shown that the method is applicable to therapy ccontrol in Hansen's disease and that a correlation between the morphology of an individual M. leprae cell and its physiological state can be achieved. In addition to the microprobe features, the LAMMS technique offers also soft ionization capability which can be utilized for laser desorption mass spectrometry (LD-MS) of isolated complex cell components. This is demonstrated for the structural elucidation of dephosphorylated free lipid A from lipopolysaccharide of Escherichia coli and Chromobacterium violaceum , respectively.