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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.

132 patients (mean age 46.9 +/- 1.4 years) with exacerbation of gastroduodenal ulcer (GDU) positive by Helicobacter pylori (HP) were examined clinically and using laboratory tests. All the patients received treatment with anti-HP drugs. Side effects were registered in 81(61.4%) patients. Negative trend in colon biocenosis occurred in all the patients. The treatment was poorly tolerated by women, aged patients and those with ulcer in the stomach. Biocenosis aggravation is indication for administration of eubiotics.

A highly efficient bacterial composition "AF" which includes representatives of two genera of microorganisms Enterococcus faecium and Lactobacillus acidophilus has been created as a result of analysis of biological properties of a number of strains of lactic-acid bacteria. Their biological properties--antagonistic activity in respect to pathogenic and conditionally pathogenic microorganisms, ability to adhesion and function in the intestine, sensitivity to antibiotics, etc., have been studied in the laboratory conditions. Prospects of the use of the given composition in production of milk products of functional effects have been shown.

Antagonistic activity of lactic acid bacteria of strain N 2585 of "Maxilin" probiotic in respect to the strains S. aureus, P. aeruginosa, E. coli, Candida albicans and their effect on the level of sustainability of the antibiotic resistant strains S. aureus, E. coli, P. aeruginosa, which are extracted from the patients with open fractures of the mandible under various course of wound process, have been studied. The studies showed that lactic acid bacteria have suppressed growth of strains Candida most actively, followed by P. aeruginosa, S. aureus and E. coli. The use of "Maxilin" probiotic allowed reducing the epidemiological significance of pathogenetic strains already in 3 to 4 days. The sensibility studies showed high activity of the lactic acid bacteria in reducing antibiotic resistance of the strains investigated. It was revealed that "Maxilin" probiotic affects Ps. aeruginosa effectively, somewhat less St. aureus and E. coli. The extracted strains demonstrated sensibility to all investigated antibiotics already in 3 to 4 days.

Such biological factors as bile, gastric juice, blood serum, amino acids and pH of the medium have been studied for their effect on the growth intensity and antagonistic activity of bacilli being the basis of biosporin and subalin. It has been established that pH of the medium within 7.0-9.0 as well as certain concentrations of the gastric juice, bile, blood serum and most of amino acids did not affect the growth of Bacillus subtilis 3 and Bacillus subtilis 2335/105. A regular decrease of growth intensity in bacilli under the increase of the gastric juice concentration or decrease of pH of the medium to 5.0-2.0 is registered. The mentioned biological factors affect differently the antagonistic properties of the studied cultures.

A new probiotic Biosporin and other commercial biopreparations based on aerobic sporulating bacteria of the Bacillus genus have been comparatively studied for their specific activity and safety. It has been established that only Biosporin is characterized by expressed antagonistic activity in respect to a wide range of pathogenic and conditionally pathogenic microorganisms including those with multiple resistance to antibiotics. Biosporin is also characterized by the absence of any negative action on the organism of animals even in the doses considerably exceeding those recommended for use.

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.

Sensitivity of 84 cultures of L. fermenti, 43 cultures of L. brevis, 13 cultures of L. buchneri and 2 cultures of L. cellobiosus to the effect of 39 types of bacteriocins produced by various species of lactobacilli was studied with the method of delayed antagonism. All the cultures of L. brevis, L. buchneri and L. cellobiosus and 65.5 per cent of the cultures of L. fermenti were sensitive to one or more such bacteriocins. The cultures of L. Fermenti, L. brevis, L. buchneri and L. cellobiosus were sensitive respectively to 37, 19, 16 and 9 types of the bacteriocins out of 39 types tested.

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.

Antibacterial activity of 272 Erwinia strains was studied. It was found that 182 or 66.9 per cent of the strains were capable of producing spontaneously antibacterial substances belonging to the class of bacteriocins; 125 bacteriocynogenic strains were divided into 25 groups on the basis of their antibacterial spectrum similarity; 57 bacteriocynogenic strains were not included into any of these groups because of their significant heterogenicity with respect to the feature studied. It was shown that most of the strains inhibited viability of the bacteria of both its own and other species. Investigation of the antagonistic activity of the Erwinia strains with broad antibacterial spectra with respect to E. coli indicative for colicins gave negative results. The study of the Erwinia strains sensitivity to the antibacterial effect of the bacteriocynogenic cultures showed that 210 out of 272 cultures were sensitive to separate bacteriocins.

Capacity for production of bactericin was found in the spheroplasts of the strains of the rodent pseudotuberculosis microbe. The author named it as pseudotuberculocin. The bacteriocin production was not detected in the initial strains of the pseudotuberculosis microbe. Pseudotuberculocin differed in the antibacterial spectrum and morphology of the growth inhibition zones formed on the plates with the indicator strains from the pesticins produced by the strains of the plaque microbe of the marmot and sandword varieties respectively and the cultures of the plaque microbe from the Transcaucasian Upland, as well as from pesticins of the spheroplasts of these strains. Production of a pesticin differing from pesticins of the rod-like forms of these strains by an ability to inhibit the growth of the homologous indicators was shown in the spheroplasts of the plaque microbe of the marmot and sandword varieties. Sensitivity of the plaque microbe strains of the marmot and sandword varieties to the pesticins of the plaque microbe strains and pseudotuberculocin was noted. With an account of the difference in the activity of the tested pesticins and pseudotuberculocin against the strains of the Frederic collection it is recommended to use this property for identifications of pesticins and pseudotuberculocin.

A nutrient medium containing 0.7 per cent of lithium chloride was tested and Yersinia pestis inhibitor was detected in 83.3 per cent of the strains on the growth tufts of 8 indicator strains isolated from a homologous focus. Lowering the lithium chloride concentration in the medium up to 0.6 per cent promoted detection of the inhibitor in a larger number of the tested strains (93.3 per cent). But even on this medium none of the indicator strains formed overall growth tufts. The subcultures of the indicator strains resistant to lithium chloride formed overall growth tufts on agar plates with lithium chloride and were sensitive to the inhibitor of the tested strains from the central Caucasus. However, during storage they lost their sensitivity to the inhibitor which did not permit their use as the test cultures.

The literature data and the results of the author studies on determination of intestine colonization resistance are presented. The mechanisms of the colonization resistance defined by the macroorganism factors and representatives of indigenic microflora are discussed. The results of the experiments with animal gnotobiotes aimed at elucidating new aspects of the colonization resistance mechanism: antagonistic interrelations between pathogenic and nonpathogenic bacteria and the role of transitory microflora, factors lowering the colonization resistance are presented. The up-to-date methods for testing the colonization resistance and the ways for its increasing are indicated.

The pattern of oxido-reductive processes and antifungal properties of the bacteria Bacillus brevis and Pseudomonas mycophaga were studied as related to the type and ratio of nitrogen sources (NH4, NO3) in the nutrient medium. The biosynthesis of antibiotics was coupled with the anaerobic pattern of metabolism, and energetic processes of metabolism varied with respect to the nitrogen source. Nitrates exerted an inhibitory effect on the enzymic systems responsible for utilization of ammonium nitrogen.

The paper describes Bacillus thuringiensis var. galleriae strains possessing a bacteriocin-like factor (factor K) which inhibits the cultures of a number of serotypes of Bac. thuringiensis. The K+ cultures exhibit no antibacterial effect on other gram-positive and gram-negative microorganisms. The maximal level of factor K is found by the 8--9th hour of cultivation. No correlation has been established between the strucutred elements in the preparations of K+ cultures and the antibacterial activity. Apparently, factor K can be transferred to other strains.