Accelerated determination of the Mycobacterium tuberculosis drug resistance with a semiliquid culture medium

: A medium was worked out whose consistence is close to liquid ones (the terminal concentration of agar-agar is 0.08%) and which enable a visual registration of growth of Mycobacterium tuberculosis (MBT) on days 3-4 after culture inoculation. The medium is based on the liquid synthetic medium of Soton, which is added 0.35% of nutrition agar and 10% (medium 1) or 25% (medium 2) of horse serum. The elaborated semi-liquid medium was used simultaneously with the standard method of absolute concentrations base on Levenstein-Jensen's medium to determine the drug resistance of 294 MBT clinical strains. The highest coincidence rate of results, in percent, was found for medium 2: for streptomycin--90.1%, for isoniazid--96.7%, and for rifampycin--96.3%, therefore, the mentioned medium can be referred to as an optimal one in a fast determination of the MBT resistance to three main anti-TB drugs. The deadline of registering the results for sensitive strains is 7 days, and for resistant strains it is 3-4 days, i.e. after the onset of primary growth signs.