FIELD: medicine.SUBSTANCE: invention is a method for reduction of tularemia pathogen resistance to cephalosporins, where a nonionic surfactant tween 80 is used as the drug in an amount of (0.5-1)% by means of which the permeability of the outer cells structures of the tularemia pathogen is increased. The studies are performed in vivo and in vitro. In the latter case, the disc-diffusion method and the serial dilution method are used, after which the studies results are evaluated according to the implemented methods. For the disc-diffusion method, Muller-Hinton agar plates are prepared in two rows, one of which is injected with (0.5-1)% tween 80, then the bacteria of the investigated tularemia strains are seeded onto the agar surface from a pre-prepared suspension containing 108 mcl/ml. After the suspension is absorbed into the agar, discs with cephalosporin antibiotics are placed on its surface, and no discs are placed on the control plates with and without tween, the crops are incubated for 24-48 hours at 37°C, the results evaluation is carried out visually by formation of zones of bacterial growth inhibition, if the latter have a diameter of 25-40 mm, then their sensitivity to the antibiotic is confirmed. Zones of inhibition are absent on the plates with medium without tween 80. In addition, for the serial dilution method, two rows of plates with a Muller-Hinton culture medium are prepared, where a cephalosporin antibiotic is administered at various concentrations, namely 25, 50, 100, 250, 500 μg/ml of medium. In parallel, the same row of plates is prepared, with tween 80 is adding to the medium at a concentration (0.5-1)%, then 0.05 ml of the test strain from the bacterial suspension containing 108 mc/ml according to the optical turbidity standard of 10 units is seeded, Muller-Hinton medium without the antibiotic and Muller-Hinton medium containing (0.5-1)% of tween 80 without the antibiotic are used as a control, the cultures are incubated at 37°C for 24-48 hours
