Biomedical subjects
Publications and source records attributed to G K Degteva.
On the basis of data obtained by the biological characterization and electrophoretic typing of Acinetobacter sp. cultures by the spectra of membrane proteins epidemiological relationships, routes of transmission and specific features of the circulation of strains causing purulent inflammatory diseases have been determined.
Analysis of clinical material from cardiosurgical and cardiotherapeutic patients and that from neonates with pyoseptic infections, hospitalized in Moscow and Gorky, has demonstrated the etiologic significance of coagulase-negative Staphylococci (CNS). Since many strains did not belong to S. aureus, S. epidermidis, or S. saprophyticus, they were species-identified in accordance with the classification by W. Kloos and K. Schleifer (1975). A variety of CNS species was observed, and their role in the development of pyoseptic infections shown, the contribution of S. epidermidis and S. haemolyticus being the greatest here. Besides S. aureus, S. xylosus was often isolated from purulent foci. A certain specificity in CNS spectrum, related to the hospital profile, was revealed. A brief modified scheme of CNS classification was developed, based on analysis of about 700 strains, in accordance with the classification of W. Kloos and K. Schleifer, that included the tests available for practical laboratories.
Various methods for sheep red cell sensitization for the preparation of erythrocytic diagnostic agent from staphylococcal proteinase were under study. Sensitization with chromium chloride yielded the best results as regarded the sensitivity of the agent, optimal sensitizing dose, and sensitin consumption. The resultant erythrocytic diagnostic agent retained about 10% of the initial enzymic solution activity. The authors have demonstrated a high specificity of the erythrocytic diagnostic agent from staphylococcal proteinase, that may be used for the serologic diagnosis of staphylococcal infection and for proteinase indication in various staphylococcal preparations.
Glucose nonfermenting gram-negative bacteria were electrophoretically typed for the extracellular protein spectra. The method permits differentiation on the generic level the cultures of such bacteria, characterized by atypical biochemistry, within 10 hours.
The beta-lactamase activity of staphylococci isolated from the nasopharynx and skin of children with destructive affections of the lungs and from blood of patients with cardiovascular diseases subjected to surgical operations was determined with acidometric and microbiological procedures. Interrelation between synthesis of beta-lactamase by the staphylococcal strains and their resistance to beta-lactam antibiotics was demonstrated. No correlation of the antibiotic resistance and the taxonomic position of the staphylococcal strains was observed.
The possibility of detecting identical strains was analyzed by comparing extracellular protein spectra of Staphylococcus aureus strains from the collection of the L. A. Tarasevich Institute for Standardization and Control of Medical Preparations. Analysis of the findings confirms that S. aureus and other Staphylococci should be characterized by their protein spectra and this marker should be present in the certificate of the strain in collections. Protein spectrum determination is obligatory for production strains.
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Dioxidine++-induced changes were shown to occur in the protein composition of the cells of Staphylococcus aureus. The most significant damages were observed in the composition of exoproteins. Dioxidine++ had a specific inhibitory effect on intracellular nuclease, which was accompanied by a decrease in virulence and disorders in the toxin formation.
Materials on the study of four outbreaks of alimentary toxinfections of staphylococcal etiology, carried out by the method of the identification of staphylococci by the spectra of their extracellular proteins, are presented. As the result of this study, the sources and transfer routes of infections have been established. The method of the identification of staphylococci by the exoprotein spectra has made it possible to find out the epidemiological chain with greater accuracy. Such identification may serve as an auxiliary method in epidemiological surveillance.
A high degree of similarity (exceeding 90%) between the electrophoregrams of the exoproducts of 31 Pseudomonas strains, including the standard species P. aeruginosa, P. maltophilia, P. putida, P. alcaligenes, P. testosteroni, P. diminuta, P. stutseri, P. fluorescens, has been shown by the method of electrophoresis in polyacrylamide gel.
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Outer membrane proteins have been studied in 76 Salmonella strains isolated from various sources and differing in their sensitivity to antibiotics, the presence of R-plasmids and a number of enzymatic properties. The outer membranes have been isolated by the modified method of L. W. Coulton and D. T. F. Wan. The study of the isolated proteins has been carried out by means of gel and disc electrophoresis in polyacrylamide gel with sodium dodecyl sulfate according to K. Weber and M. Osborn. The composition of the proteinograms thus obtained has revealed the presence of essential differences between hospital strains and cultures isolated from animals and from the environment in sporadic infections, as well as between strains belonging to different serovars. The possibility of using the characterization of outer membrane proteins of salmonellae in epidemiological investigations is discussed.
The genome characterization of the typing strains for all 13 species of the genus Staphylococcus, included into the Approval List of the Names of Bacterial (1980), is presented. The nucleotide composition of DNA (28-33% of GC) did not permit the differentiation between staphylococcal species, but some of the groups of these species could be differentiated by the size of their genome (0.6-1.6 X 10(9) daltons). Differences in the degree of similarity between the nucleotide sequences of the DNA of all species (5-6% of DNA homology) made it possible to suggest raising the genus Staphylococcus to the rank of the family Staphylococcaceae fam. nov. The hypothetical classification scheme of this family is presented for discussion.
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Hardware and software for the automatic comparison of densitograms, based on the evaluation of their autocorrelation characteristics, can be used for establishing the characteristics of circulating staphylococcal populations and for their epidemiological marking.
The comparison of the spectra of the membrane proteins of 12 typing strains of coagulase negative staphylococci has revealed differences which probably reflect the distinctive features of membrane proteins, intrinsic to individual bacterial species.
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The study of the spectra of the extracellular proteins of 45 museum cultures and 391 newly isolated cultures has demonstrated that these spectra are the strain characteristic of staphylococci. A method for the identification of staphylococci by the spectra of their extracellular proteins is proposed.