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The medicinal resistance of salmonellae isolated in the USSR and the Slovak Republic in 1987-1988 was studied. The resistance of salmonellae at this period was shown to decrease in comparison with the period of 1985-1986. The study revealed the presence of multiresistant strains capable of the conjugative transmission of some resistance markers. The minimal inhibiting concentrations of antibiotics to which salmonellae proved to be resistant were determined.

An active substance (designated as 6666-4), which proved to have considerable bae ter ios ta t ic activity on ac idres i s t ing bac te r i a in vitro, was isolated f rom a culture of one of the act inomycetes during our sea rch for antibiotics. The unpurified antibiotic was chromatographed on a si l ica gel column t rea ted with 0.1 sodium hydroxide. The column was washed with chloroform to remove impuri t ies , the active substance was eluted with acetone, and after recrys ta l l iz ing it f rom methanol, we obtained it as color less needle-l ike c rys ta l s with a min imumbac te r ios t a t i c concentrat ion o f 0.03 ~g /ml (the tes t o rganism was Mycobact. phlei se r ies dilutions method). The homogeneousness of this product was confirmed by thin layer chromatography on aluminum oxide using the solvent sys tems methanol -ch loroform (6:94) and methanol-ethyl acetate (2:98) ; the ch romatograms were developed with iodine vapors, concentrated sulfuric acid, and bioautographical ly (the tes t culture was Bac. subtilis).

Data on studying various conditions for prolonged storage of Micromonospora are presented. It was shown that Micromonospora were satisfactorily stored under conditions of all maintenance methods used. The optimal methods were the following: storage of Micromonospora on agarized media under a layer of vaseline oil, storage of Micromonospora in the form of a mature submerged culture on liquid media optimal for its growth and development. Stimulating effect of low temperature on the spore germination was shown.