Interaction of bacteria and red blood cells

The interaction of staphylococci, streptococci, meningococci, enterobacteria, leptospires and other microorganisms with red blood cells is considered. Three forms of the interaction of bacteria and red blood cells are discussed: adhesion, the influence of secretory factors on red blood cells, the action of pathogenic bacteria on hemoglobin. The applied aspects of the interaction of bacteria and red blood cells in the human body are presented in accordance with the results of clinical and laboratory studies.     

Microbial biocenosis of the nasal mucosa in healthy persons and in Staphylococcus carriers

The normal microflora of the nasal mucosa in man is differentiated into main, complementary and casual microflora, taking into account its isolation rate and characteristics of microbial contamination. The main microflora of adults, in contrast to children, is represented, in addition to coagulaso-negative (CN) staphylococci, by bacteria of the genus Corynebacterium. In staphylococcal carrier state a decrease in the isolation rate and the amount of bacteria belonging to the main and complementary microflora (CN staphylococci, Micrococcus, Streptococcus, Bacillus) was observed. Moreover, in carriers the weakening of the degree of association between CN staphylococci, Micrococcus, Corynebacterium, Streptococcus in symbiotic pairs was noted. In the absence of S. aureus carrier state the main and complementary microflora was characterized by the combination of the factors of antagonism and persistence, while in carrier state the complex of colonization factors was defective in the main microflora and well pronounced in coagulase-positive staphylococcal strains and enterobacteria.     

Biotyping of pathogenic cocci using mathematical methods

The differential information content of biological signs in the ecology of different staphylococcal and streptococcal species has been studied by the mathematical method. The method for the intraspecific differentiation of staphylococci, streptococci and gonococci into pathovars with the use of programs for the computerized analysis of the material has been proposed. The mathematical models of strain virulence in different coccal species are described.     

Modification of antibiotic resistance in microbial symbiosis

In antibiotic therapy it is necessary to use drugs active against the pathogen in its association with the host normal microflora. The aim of the study was to investigate modification of antibiotic resistance under conditions of the pathogen association with the representatives of the host normal microflora and to develop the microbiological criteria for determining effectiveness of antibacterials. Modification of microbial antibiotic resistance was investigated in 408 associations. Various changes in the antibiotic resistance of the strains were revealed: synergism, antagonism and indifference. On the basis of the results it was concluded that in the choice of the antibiotic active against Staphylococcus aureus and Streptococcus pyogenes the preference should be given to oxacillin, gentamicin and levomycetin, since the resistance of the pathogens to these antibiotics under the association conditions did not increase, which could contribute to their destruction, whereas the resistance of the normoflora increased or did not change, which was important for its retention in the biocenosis. The data on changeability of the antibiotic resistance of the microbial strains under the association conditions made it possible to develop microbiological criteria for determining effectiveness of antibiotics in the treatment of inflammatory diseases of microbial etiology (RF Patent No. 2231554).     

The antilysozyme activity of Mycobacterium tuberculosis L forms

The method for the detection of antilysozyme activity (ALA) in M. tuberculosis L forms was developed. The level of ALA in M. tuberculosis L forms isolated from patients with different clinical forms of the disease varied within 1-5 micrograms. M. tuberculosis L forms with the ALA level > 4 micrograms were isolated from patients with the progressing course of the disease. The method for the prognostication of the course of the tuberculous process in the lungs by the results of the antilysozyme test was proposed.     

Lysozyme activity of pneumococci]

Examination of 329 pneumococcal strains showed that 41.2 per cent of the cultures had lysozyme activity. The frequency of the lysozyme feature depended on the method used. The lysozyme active strains were more frequently isolated from patients than from healthy persons and characterized by antibiotic resistance. The lysozyme feature correlated with the pneumococcal virulence with respect to albino mice, capacity for capsule formaiton and resistance to phagocytosis.     

The antilysozyme activity of meningococci

The antilysozyme activity of 184 meningococcal strains was studied. Such activity was found in all strains within the range 1-25 micrograms/ml, which was due to the heterogeneity of bacterial population. Strains varying in the total level of their lysozyme activity differed in the population structure by this sign. Preparations inhibiting antilysozyme activity could be differentiated according to the character of their action by the method of the population analysis. In the process of phagocytosis the selection of clones with a high level of antilysozyme activity was found to occur. The antilysozyme factor, heat resistant protein with a molecular weight of 10,000-30,000 D, was sensitive to trypsin.