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Biologically active compounds of spore-forming bacteria of Bacillus genus, which have antagonistic effect on opportunistic and pathogenic microorganisms, are characterized in the review. Information about known to date antibiotics and bacteriocins produced by Bacillus species is presented.

Aim: To study the effect of growth medium content on antagonistic characteristics of "Pashkov" strain of B. pumilus., Materials and Methods: The following strains were used in the study: B. subtitlis 3H, B. subtitlis 534, B. subtitlis 1719, B. pumilus "Pashkov". Test strains from collection of Tarasevich State Institute for Standardization and Control of Medical Biological Preparations were used for determination of antagonistic activity. Growing of B. pumilus cultures on medium (No. 9, No. 5, VK-2, Spizeisen, and L-broth) was performed by periodic cultivation during 72 h in conditions of continuous aeration at 37 degrees C. Inhibiting effect of obtained samples was assessed on growth kinetics of test strains using microbiological analyzer with plan-table photometer "BIOSCREEN/iEMS--reader MF" (LabMetod, Finland)., Results: Expressed antagonistic characteristics were revealed during cultivation on media No. 9 and No. 5 with maximal expression on day 3. Addition of lactose to medium No. 9 resulted in increase of bacteriostatic effect (BSE) against both individual strains and all test strains--up to 16% in average. Selection of optimal concentrations of different components allowed to develop a new growth medium which provides maximal antagonistic activity in studied strain of B. pumilus., Conclusion: Effect of growth medium content on antagonistic characteristics against pathogenic and opportunistic bacteria was confirmed on the example of cultivation of spore-forming strain "Pashkov" of B. pumilus. Optimization of carbohydrate, salt and other components of growth medium allowed to increase up to 100% the BSE of "Pashkov" strain of B. pumilus against both individual and all test strains. This study opens perspectives for generation of compounds with directional probiotic effect.

The oral administration of the therapeutic doses of tetracycline, pefloxacin, ampicillin, cephalexin, rifampicin, sisomicin to Wistar rats for 5 days was accompanied by a decrease in the total number of lactobacilli in feces and by changes of the species spectre of these microorganisms. In those rats species, never found in intact animals, could be revealed rather frequently. All antimicrobial preparations administered in this investigation induced a decrease in the proportion of antibiotic-sensitive cultures and led to the selection of strains having multiresistance and increased antagonistic activity with respect to Pseudomonas indicator strain. The possible relationship between the markers antibiotic resistance and antagonistic activity in lactobacilli is discussed.

The damaging of V. cholerae enterotoxin on anaerobic dehydrogenases of different species of opportunistic microorganisms has been revealed. Experiments, carried out both in vivo and in vitro, have shown that under certain conditions this enterotoxin may act as one of the factors of the intra- and interspecific antagonism of bacteria.

The relationship between 433 V. cholerae strains and 571 enterobacterial strains, isolated from different ecosystems, have been studied by the method of "delayed antagonism". The direct correlation between the virulence of V. cholerae and the width of the spectra of their antagonistic activity towards indicator bacteria was detected. The expediency of studies on the role of the vibriocinogenic factor in the survival of V. cholerae in different ecological systems is substantiated.