METHOD OF DETERMINING DRUG SUSCEPTIBILITY OF TUBERCULOSIS MYCOBACTERIA Russian patent published in 2005 - IPC

FIELD: medical microbiology.

SUBSTANCE: invention relates to microbiological diagnostics of the drug susceptibility of tuberculosis mycobacteria to antituberculous preparations. Method provided by invention relates to mycobacteria M. tuberculosis, which is realized on nutrient medium consisting of two layers. Preparation of biphasic medium comprises placing 2 ml sterile perfluorodecaline into test tube followed by placing 2 ml Shkolnikova medium over it to form system, wherein lower phase occupies heavier perfluorodecaline and higher phase nutritive broth. To be diluted in the medium, different weighed specimens of principal antituberculous preparations are prepared from pure substances. Powders are first diluted with sterile distilled water and thus prepared solution is introduced into nutrient medium by 0.1 ml portions to provide final concentration of each preparation in medium corresponding to critical concentration. Strain being tested is placed in test tubes in the form of microbial slurry in amounts 2 ml for each test tube. Microbial growth in test tubes with antituberculous preparations is estimated in comparison with control growth with the aid of 2% solution of triphenyltetrazolium chloride, which is added into each of 5 test tubes in amounts 0.1 ml on the 8^th culturing day. Test tubes are the incubated for further 24 h. During this period, colonies if mycobacteria grown in interphase border acquire vinous coloration. Culture is regarded as stable if coloration intensity of colonies grown in interphase border roughly corresponds to coloration intensity of control. When accuracy data regarding determination of drug susceptibility is compared to reference methods, the data were found to be completely the same.

EFFECT: reduced determination time (to 9 days).

2 cl, 2 tbl