FIELD: microbiology.
SUBSTANCE: MALDI-TOF mass spectrometric method for determining microorganism resistance to antibacterial preparations is proposed. The method includes the short-term cultivation of a microorganism on dense nutritional medium with a concentration gradient of an antibacterial preparation, formed by diffusion of an antibiotic from a carrier, and the application of intact cells to a MALDI target. Mass spectra are obtained in a linear positive mode of a spectrometer in the range of a ratio m/z=2000-10,000 Da, as a matrix, α-cyano-4-hydroxycoric acid is used. The microorganism resistance to the antibiotic is determined by the presence or the absence of a marker peak at m/z=9200-9700 Da in spectral profiles obtained from cells taken from the surface of the nutritional medium at distances, relatively to the carrier of the antibacterial preparation, equal to boundary values of a diameter of a growth suppression zone (mm) or minimum antibiotic concentration (mg/l), which are criteria of sensitivity and resistance of the microorganism.
EFFECT: invention provides for the reduction in time of determination of the resistance of microorganisms isolated from biological material of patients to antimicrobial preparations, the selection of an adequate therapy scheme.
1 cl, 4 dwg, 4 ex
