[Microbial model Halobacterium salinarum in screening of synthetic analogues of antibiotic turbomycin A with anticancer activity].

The microbial test-system based on cultivation of Halobacterium salinarum developed earlier for screening inhibitors of sterol biosynthesis and proposed for screening anticancer antibiotics, proved to be efficient in revealing anticancer compounds among derivatives of tris(1-alkylindol-3-yl)methylium, synthetic analogues of antibiotic turbomycin A. Most of the methane sulfonate and chloride salts of such compounds, investigated with the help of the H. salinarum test-system, showed no activity (MIC>32 mcM), while several derivatives, containing N-butyl or N-pentyl substituents were rather active against the bacterial strain. The MICs of them against H. salinarum were 8 mcM for total and 1 mcM for partial inhibition of the bacterial growth. The results of the study correlated with the results of other investigations that revealed anticancer activity of such compounds in tumor cell cultures. Therefore, the H. salinarum test-system demonstrated its availability for screening compounds with anticancer activity.

[Comparative in vitro activity of ampicillin, cefoperazone, their combinations with sulbactam and other antibiotics with respect to staphylococci and pneumococci]. / Sravnitel'naia aktivnost' in vitro ampitsillina, tsefoperazona, ikh kombinatsii s sul'baktamom i drugikh antibiotikov v otnoshenii stafilokokkov i pnevmokokkov.

Antibiotic susceptibility of 225 Staphylococcus strains and 42 Pneumococcus strains was assayed with the method of serial microdilutions. Methicillin resistant Staphylococcus strains (S. aureus and coagulase negative strains) were characterized by high susceptibility to cephalosporins and ampicillin + sulbactam combination, as well as to ciprofloxacin, rifampicin and vancomycin (70 to 100 per cent of the susceptible strains). Less than 50 per cent of the strains was susceptible to erythromycin. The methicillin resistant Staphylococcus strains preserved their high susceptibility to vancomycin and rifampicin (the coagulase negative strains also preserved their susceptibility to ciprofloxacin). Four Pneumococcus strains with the intermediate resistance to benzylpenicillin were isolated (for 9.6 per cent of the strains the MIC was 0.12 to 1.0 micrograms/ml). The growth of 2 out of these 4 strains was inhibited by the ampicillin + sulbactam combination in a concentration of less than 0.5 micrograms/ml and by cefotaxime and the cefoperazone + sulbactam combination in a concentration of less than 1.0 micrograms/ml. The growth of the other 2 strains was inhibited by betalactams in concentrations higher than the above mentioned.