Bacterial Infection Department

The Head of the Department is Y.F Beliy, Doctor of Medical Science.

The main lines of research and development are: the structural and functional properties of toxins and factors of bacterial pathogenicity; genetic determinants of pathogenicity factors; molecular, biological and immunological diagnostic test systems; development and evaluation of the effectiveness of recombinant and DNA vaccine products; search for botulinum toxin antidotes; creation of genetic constructs for the synthesis of hybrid targeted proteins.

From April 2009 until later reformation, the structure of the department included laboratories for associated infections, anatomy of microorganisms, and biophysical and radioisotope studies, which previously formed the basis of the department of structure and function of microorganisms.

Molecular Basis of Pathogenicity Laboratory (with the staphylococcal infections group)

The Head of the Laboratory is Y.F Beliy, Doctor of Medical Science.

The laboratory studies the interaction of bacteria with eukaryotic cells at a molecular level using anaerobic microorganism Clostridium difficile, C.tetani, C.perfringens and others as a model. Research is being conducted into the architecture of the cell wall and the role of microorganism surface structures in virulency and the formation of host immunity. Modern methods of diagnosis and immunotherapy are developed for infections caused by anaerobic microorganisms with the application of molecular genetic technology and molecular biochemistry.

Genetically engineered constructions have been created and piloted on the basis of toxins C.difficile, C.tetani, C.histolyticum and C.perfringens. Particular attention in research is given to bacterial proteins interacting with active instruments of eukaryotic cells and influencing the process of phagocytosis. Using different domains of toxins, immunoregulatory activity for bacterial products is studied with the purpose of creating new medicinal products for treatment, prevention and diagnosis.

Using computer modelling, a fundamentally new concept for the structure of the bacterial cell wall is under development. This takes into account the most recent data regarding structural biochemistry, physiology, organic chemistry, and molecular genetics and contributes to further understanding of the mechanisms of formation and creation of the bacterial cell wall, as well as the processes of transport of enzymes and other microbial proteins to the surface of the cell and their secretion into the extracellular space.

With the application of epidemiological and biological methods, new approaches are in development for preventive immunization of clostridiosis in wounds (tetanus and gas gangrene) that are the most severe complications of injuries and surgical procedures. A complex medication is in development that contains protective antigens against tetanus and gas gangrene pathogens. A significant component of current work is the isolation in pure form and study of fundamental toxic microbe products (tetanus toxin and tetanolysin) as well as the isolation of previously unknown cell wall components of pathogenic clostridium. The proteins obtained present an interest not only from a practical point of view, but also as components of new vaccine sources, as well as for theoretical purposes as factors involved in the pathomechanism for tetanus and gas gangrene.

The group of staphylococcus infections has been functioning in the laboratory since 2010.

The main lines of research of the group are the following:

  • study of the molecular epidemiology of staphylococcus infection in the Russian Federation, enhancement of epidemiological surveillance and tactical measures against infection connected to the provision of medical assistance;

  • research of the properties and development of diagnostic agents for the detection of new enterotoxins and enterotoxin-like staphylococcus peptides.

Within the framework of the first line of research, the structural features of the organization of the genomes of S. aureus and coagulase-negative staphylococci (CoNS), the role of mobile genetic elements in the microevolution of pathogens of hospital infections and the molecular mechanisms of adaptation of staphylococci to various hosts are being studied. The first epidemic strains of S.aureus (MRSA) circulating in medical clinics in several regions of the Russian Federation were identified as a result of research. Using molecular and genetic methods, including full genome sequence analysis, their genetic relationship with epidemic MRSA strains circulating in other countries was proved. The need for molecular and genetic monitoring of MRSA in clinics within the RF was scientifically justified. New types of SCCmec genomic islands were identified in the CoNS genome determining resilience to beta-lactam antibiotics.

Factors influencing the production of S. aureus enterotoxins are being studied as part of a secondary line of research, and the search for substances that block their expression is being carried out. Together with the clostridiosis laboratory staff, recombinant staphylococcal enterotoxins C, D, E, H, G, I, K and TSST-1 and specific diagnostic serums for them have been obtained. Test systems have been developed for indication of enterotoxins with sensitivity of 1-5 ng/ml.

The group is a of a unique holder of a collection of S.aureus reference strains producing a number of types of toxins, reference strains of a number of types of staphylococcus, creating a DNA bank of epidemic strains and a clinical isolate bank. These collections are the basis for fundamental, practical and scientific developments.

Clostridiosis Laboratory

The head of the laboratory is A.N Noskov, Doctor of Biological Science.

The main lines of activity of the laboratory are the following:

  • Development of a recombinant botulism vaccine.
    The main aim of the study is assessment of the immunogenicity of various type A neurotoxin domains. Genetic constructs have been obtained that ensure the production of non-toxic recombinant enzymatic and receptor-binding domains of type A, B, C, E, F, and G neurotoxins. It has been shown in a model of type A neurotoxin recombinant domains that they hold immunogenic properties, but are capable of causing the formation of protective immunity to varying degrees. The main drawback of recombinant neurotoxin domains is their insolubility. Therefore, main efforts are concentrated on obtaining recombinant domains in soluble form. Once this issue can be overcome, obtaining a polyvalent botulism vaccine will be closer to a reality.

  • Assessment of possibility for DNA vaccine development.
    The aim of research is investigation of the possibility of obtaining a DNA vaccine against bacterial toxins. Constructs were obtained on the basis of vector plasmid pcDNA3 in which, under the control of CMV regulatory sequences, there are non-toxic receptor-binding domains of exotoxin A of the Pseudomonas aeruginosa toxin, as well as type 1 and 2 shiga-like toxins. The DNA vaccines obtained have been embedded into the S.typhi 21A strain, which is used for their delivery inside the eukaryotic cells. Research results have shown that for oral vaccination strains in mice only DNA construction with the exotoxin A domain provided defense for animals against the action of homologous toxins.

  • Construction of hybrid targeted proteins.
    The main aim of research is clarification regarding the possibility of using receptor and binding domains of botulinum neurotoxins for the delivery of treatment proteins to the tissue of the nervous system. Genetic constructions were obtained, providing an accumulation of recombinant proteins made up of receptor and binding domains of type A neurotoxins on one hand and protein A staphylococcus or С3 C.botulinum exoenzyme on the other. In the given case, protein A serves as a marker for the registration of penetration of the hybrid protein inside the neurons, while exoenzyme C3 has the ability to accelerate the regeneration and growth of neurofibres. Further work will concentrate on obtaining information on the functional properties of new proteins.

  • Development of immunological and molecular and biological methods of identification for toxin-producing pathogenic bacteria.
    Bacterial toxins such as botulinum types A, B, C, E, F and G, shiga-like toxin types 1 and 2, the heat-labile enterotoxin of coliform bacillus, diphtheria toxin and exotoxin A pseudomonas serve as the research subject. An immunoenzyme method and polymerase chain reaction are used to identify these toxins and their genes.

Laboratory indications and ultrastructural analysis of microorganisms

The head of the laboratory is V.G. Zhukhovitskiy, Doctor of Medical Science.