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.     

The antilysozyme activity of bacteria in the genus Klebsiella

The ability to inactivate lysozyme was found in representatives of three species of the genus Klebsiella bacteria: K. pneumoniae (117 strains), K. rhinoscleromatis (104 strains), K. ozaenae (90 cultures). The test cultures displayed a different antilysozyme activity, inactivating from 2 to 30 micrograms/ml of the enzyme. Taking into account the lysozyme role in the immunity and chitin synthesis processes in the organism of insects, the inactivation of the enzyme by Klebsiella may be considered as one of possible mechanisms of the entomopathogenic action of these bacteria.     

The antilysozyme activity of yeasts in the genus Candida

The fungi of the genus Candida isolated from patients with oral mucosa candidiasis and from candidiasis carriers have been studied for their antilysozyme activity. These fungi (Candida albicans, C. tropicalis, C. krusei, C. quilliermondii) are antilysozyme-active. A high antilysozyme activity of the fungi isolated from patients with oral mucosa candidiasis permits supposing that the presence of this trait may be one of the factors of microorganism pathogenicity. The effective antimycotic therapy (clotrimasole, sanguirhitrin) decreases the antilysozyme activity of fungi of the genus Candida.     

Method of determining the antilysozyme activity of microorganisms

The method for the determination of the antilysozyme activity of microorganisms is described. The method consists in the cultivation of the strains under study in a lysozyme-containing medium, and the effect of lysozyme inactivation is determined from the growth of Micrococcus luteu S indicator strain adjacent to active strains. The quantitative evaluation of this property is presented. The study of 1 296 strains belonging to 9 genera has disclosed that antilysozyme activity occurs most frequently among Gram-negative bacteria.     

Effect of medicinal plants on the antilysozyme activity of microorganisms]

Medicinal plants effect on antilysozyme activity of E. coli, Klebsiella, S. aureus, Candida, Bifidobacterium, Bacteroides, Clostridium was evaluated in vitro. It was demonstrated that the effects differed substancially according to the microorganism taxonomy. The experimental data on the plants inhibitory activity may be used for elaboration of effective regimes of infections and disbiosis treatment.     

Screening of plasmids in the bacteria of the genus Bacillus with antilysozyme activity

In the study of the microbiocenosis of the distal section of the patients' large intestine Bacillus strains with antilysozyme activity (ALA) were isolated. In B. cereus strain 26 with pronounced expression of antilysozyme factor the plasmid sized approximately 100 kb was detected. The transformation of the isolated plasmid in cells of B. cereus non-plasmid strain IP5832 the localization of genes encoding ALA and resistance to kanamycin was determined. The production of ALA factor in the recombinant clone of B. cereus strain IP5832 corresponded to the clinical isolate of B. cereus 26. The replicon of the detected plasmid could be used for the determination of the coding sequence of the antilysozyme sign of bacilli. Genetic determinants of antilysozyme factors and kanamycin resistance may be used for the construction of vector systems of cloning in bacilli.     

Influence of chemical analogue of extracellular microbial autoregulators on antilysozyme activity of bacteria

Modifying action of C7-alkyloxybenzol (methylresorcin) on the antilysozyme activity (ALA) of opportunistic microorganisms (Bacillus cereus, Klebsiella pneumoniae, and Escherichia coli) was studied. C7-alkyloxybenzol (C7-AOB, methylrezorcin), which was used as chemical analogue of microbial autoregulators, was added to growth medium containing microorganisms, which were cultivated until entered stationary phase. Isolation of clones was performed by seeding of 24-hours broth culture on solid growth medium, and then ALA was measured using photometric method. Modifying action of C7-AOB on ALA characteristic-based population structure of B.cereus, K. pneumoniae, and E. coli was revealed. Maximal effect was detected when the concentration of C7-AOB was in range 1-10 mcg/ml. Decrease of mean ALA level caused by C7-AOB was linked to decrease of proportion of clones with high and intermediate ALA level, increase of proportion of clones with low level of lysozyme inhibitor, and emergence of clones lacking ALA in the population.     

Characteristics of Klebsiella pneumoniae plasmid bearing the markers of drug resistance and antilysozyme activity

Electrophoretic study of the profile of plasmid DNA in agarose gel has shown the presence of a plasmid with a molecular weight of 55-60 MD in K. pneumoniae strains possessing antilysozyme activity. Plasmid pAlz60 of K. pneumoniae 22-110, isolated from the blood of a septicemia patient, is a fi- type conjugative plasmid. This plasmid is transferred to recipient strains of different species of enterobacteria with a frequency of 1 X 10(-5) to 1 X 10(-7). Simultaneously with the transfer of the plasmid, recipient cells inherit the antilysozyme markers and resistance to a number of drugs. The discovered plasmid has one restriction site for each of endonucleases EcoRI and XhoI and 16-20 sites for restrictases KpNI, BglII and Hind III.     

Circadian rhythms of antibacterial resistance, coagulase and antilysozyme activity of Staphylococcus aureus

AIM: To determine daily dynamics of antibacterial resistance as well as antilysozyme and coagulase activity of S. aureus strains. MATERIALS AND METHODS: On an example of clinical strains of S.aureus isolated from patients with surgical infections daily dynamics of biological characteristics of staphylococci was studied. After 12 hours of incubation strains were tested for coagulase activity by standard method (test tube method), antilysozyme activity by photometric method, and antibacterial resistance by method of serial dilutions in agar. Tests were repeated each 3-hours during a day. RESULTS: Variation of levels of studied biological characteristics of staphylococci during a day was revealed. Structures of coagulase and antilysozyme circadian rhythms had some differences in different S. aureus strains. Alongside with it, similarity in temporal expression of such biological characteristics of staphylococci as antibacterial resistance and antilysozyme activity was noted. CONCLUSION: Obtained data open prospect to use biorhythmological approach in study of biological characteristics of microorganisms during evaluation of their mechanisms of adaptation to changing environmental conditions. Chronobiological approach allows to reveal periods of maximal expression of S. aureus characteristics that could be used for increasing of effectiveness of antibacterial treatment by the choice of optimal time for administration of antibiotic.     

Intragroup serotyping of meningococci

The method for obtaining antisera to meningococci of different serotypes are described and the scheme for the preparation of serotyping is presented, as well as the method for the preparation of the determinate fraction of serotype 2. Antisera to typing antigens 1, 2, 2-7, 2-10, 4, 5, 6, 8 (1) have been obtained, their specificity tested in parallel experiments with American and French typing sera. When typing meningococci, the use of antisera to purified protein antigen 2 is recommended.     

The endotoxin-liberating effect of antibiotics on meningococci in vitro

Three strains of Neisseria meningitis (two endotoxin-liberating and one in vitro variant non-liberating) were studied during treatment with MIC and 100 times MIC values of benzylpenicillin and chloramphenicol in a chemically-defined, protein-free medium. Treatment with the highest dose of benzylpenicillin had the most rapid effect on meningococci, although the antibacterial effect was the same for the two penicillin concentrations after 20 h. Chloramphenicol treatment showed a much slower antibacterial effect. After 2 h of antibacterial treatment, an increase of filtrable endotoxin in the medium was found for the endotoxin-ligerating strains only when the highest penicillin dose was used. During the same period there was a rapid cell death. After 20 hours of treatment, however, the endotoxin-liberating strains treated with high and low concentrations of penicillin had a markedly reduced content of filtrable endotoxin, compared to the controls and to the cultures treated with chloramphenicol. Antibacterial treatment had no, or only minimal, effect on the total content of endotoxin in the cultures, compared to the untreated controls. The endotoxin non-liberating strain had about the same total content of endotoxin as the liberating strains, but did not liberate filtrable endotoxin into the medium unless filtered with a much higher pressure through a filter with smaller pore size.     

Growth-phase associated changes in the reproductive capacity, intracellular polyamines, and antilysozyme activity inEscherichia coli batch culture

Growth-phase associated changes in and relationships between the specific growth rate (μ) characterizing the reproductive capacity of the cells, the contents of intracellular biogenic polyamines (BPA), such as putrescine (P), cadaverine (C), and spermidine (S), and antilysozyme activity (ALA) were studied in 37 strains ofEscherichia coli grown in batch culture on solid medium. A decrease in μ upon the transition of the culture to the stationary growth phase was accompanied by a decrease in the pool of free BPA, mainly P and C, and by the appearance of ALA. The interrelations between the parameters studied were described as a complex of direct and negative correlations; the combination of low initial P and C contents, reduced P/S and C/S ratios, and a high level of ALA was designated as afactor of slight inhibition ofE. coli reproduction. It is argued that BPA and ALA are integrated in a system controlling both the metabolism and stability of peptidoglycan inE. coli.     

The bactericidal action of human neutrophils on meningococci in vitro

32 Russian patients with late complement component deficiency (LCCD) were immunize with tetravalent meningococcal polysaccharide vaccine (A + C + W135 + Y). Their immune response and infectious morbidity rate were followed for 6 years and the partial protective efficacy of vaccination was demonstrated. As the antibody-mediated complement-induced bactericidal activity of plasma was completely absent in persons with LCCD, the bactericidal action of human neutrophils on meningococci of groups A, W135 and B was studied under the conditions of incubation with serum samples collected from persons with LCCD before and after vaccination. In LCCD serum alone the exponential growth of meningococci was observed, while the addition of human neutrophils resulted in the essential inhibition of the growth of meningococci (up to their complete elimination). The proportion of serum samples stimulating the elimination of group A and W 135 meningococci by neutrophils was almost 40% of the serum samples collected before vaccination and significantly increased among the serum samples collected after vaccination (up to 84%) or revaccination (up to 90%). At the same time the capacity of an individual serum sample to promote the bactericidal effect of neutrophils against meningococci correlated with its content of specific anti-polysaccharide IgG and IgM antibodies, as well as antibodies to the inner core of lipopolysaccharide. The interaction of neutrophils with meningococci was significantly inhibited after incubation in heat-inactivated serum, suggesting that this interaction was partly mediated along the following path: the binding of IgM and IgG antibodies with bacteria--the activation of complement and the deposition of C3 complement on bacteria--the binding of meningococci with CR3 receptors of neutrophils.     

The role of the antilysozyme activity of Shigella flexneri as a factor controlling the degree of its resistance to the lytic action of bacteriophages

The level of the antilysozyme activity of S. flexneri in ensuring the high level of their phage resistance has been studied. The realization of the phage protective effect of antilysozyme activity has been noted to occur due to disturbances in the lysis of infected bacteria by phage-synthetized lysozyme-like enzyme. The direct relationship between the level of the lysozyme production of bacteriophages and their capacity for overcoming the antilysozyme protection of the host bacterium has been shown.     

Phasic changes in reproductive potential, intracellular polyamines and antilysozyme activity in Escherichia coli in periodic culture

Growth-phase associated changes in and relationships between the specific growth rate (mu) characterizing the reproductive capacity of the cells, the contents of intracellular biogenic polyamines (BPA), such as putrescine (P), cadaverine (C), and spermidine (S), and antilysozyme activity (ALA) were studied in 37 strains of Escherichia coli grown in batch culture on solid medium. A decrease in mu upon the transition of the culture to the stationary growth phase was accompanied by a decrease in the pool of free BPA, mainly P and C, and by the appearance of ALA. The interrelations between the parameters studied were described as a complex of direct and negative correlations; the combination of low initial P and C contents, reduced P/S and C/S ratios, and a high level of ALA was designated as a factor of slight inhibition of E. coli reproduction. It is argued that BPA and ALA are integrated in a system controlling both the metabolism and stability of peptidoglycan in E. coli.     

The drug sensitivity of meningococci and the characteristics of its determination

The results obtained in the study of antibiotic and sulfamide sensitivity of 197 Neisseria meningitidis strains of groups A, B and C, isolated from the spinal fluid and blood of patients with meningococcal infection hospitalized in the 2nd Clinico-Infectious Hospital, Moscow, in 1984-1989 and studied with the use of the disc diffusion method and the method of serial dilutions of antibiotics in solid culture media, are presented. As revealed in this study, N. meningitidis strains retained their high sensitivity to penicillin and ampicillin (MIC50 = 0.016 and 0.032 micrograms/ml respectively). Sensitivity to tetracycline decreased (MIC50 = 0.5 micrograms/ml) and to rifampicin increased (MIC50 = 0.063 micrograms/ml). 48.5% of strains were resistant to streptomycin. In recent years the proportion of N. meningitidis, resistant to sulfanilamide preparations, significantly decreased and MIC50 was equal to 2.5 micrograms/ml in comparison with 5-10 micrograms/ml in the preceding period. The results of testing sensitivity to antibiotics by both methods coincided. Still the disc diffusion method can be used in epidemiological surveillance on meningococcal infection, while for more exact differentiation of N. meningitidis strains the use of the method of serial dilutions is necessary.