Well-forgotten old
New viruses interacting with bacteria – pathogens of nosocomial infections have been discovered
Acinetobacter baumannii, causing outbreaks of infection in medical institutions. The results of the work are published in the journal Viruses .
I would have known where to fall, I would have laid straws
The problem of nosocomial or nosocomial infections is one of the most important for modern healthcare. In many countries, there is an increase in infectious morbidity in hospitals of medical institutions, which is significantly associated with the spread of strains of microorganisms resistant to various antibacterial drugs.
Today, due to the high level and wide range of natural and acquired resistance to various antibiotics, a representative of the bacteria of the genus Acinetobacter – Acinetobacter baumannii – is one of the most significant pathogens worldwide. In intensive care and intensive care units, as well as in burn departments, this microorganism can cause the development of various infectious complications: from hospital pneumonia to brain abscesses. This bacterium has mechanisms that provide resistance to the vast majority of antibiotics, disinfectants, drying, and ultraviolet irradiation. Its pathogenicity is due to the combined effect of a number of factors, one of which is capsular polysaccharides – surface structures that form a thick protective layer (capsule) around the bacterial cell.
Everything new is well-forgotten old
Viruses are the natural enemy of bacteria. The property of certain strains of viruses to infect and kill specific types of bacteria – the cause of various infections, was investigated at the beginning of the XX century. Bacteriophages were discovered in 1915 by the British microbiologist Frederick Twort and in 1917 by the Canadian employee of the Pasteur Institute in Paris – Felix D'herrel. Later, in 1934, D'herrelle came to the Soviet Union and took part in the organization of the Bacteriophage Research Institute in Tbilisi. But the appearance of antibiotics allowed us to forget this area of research for a long time. With the advent of multi-resistant bacterial strains resistant to many antibiotics, the search for other ways to fight infections has become relevant again. Microbiologists have returned to the study of viruses called bacteriophages or phages as an alternative as drugs for bacterial diseases.
Scientists have studied lytic bacteriophages, that is, those that, after infection of a bacterial cell and a period of reproduction, quickly destroy the bacterium, releasing their offspring. The use of these phages, as well as enzymes and proteins encoded in their genetic material, is one of the possible approaches to solve the problem of the spread of antibiotic-resistant strains of A. baumannii and other bacterial species.
In the figure "Lytic cycle of virus development": 1-2 – introduction of viral DNA into a bacterial cell, modification of bacterial vital activity; 3 – replication of phage DNA and synthesis of viral proteins; 4 – formation of mature viral particles; 5 – lysis (dissolution) of a bacterial cell, the release of new phage particles
Lytic phages do not affect the normal microflora, respectively, do not cause the development of dysbiotic processes; bacteriophages are able to increase their numbers until all bacterial cells sensitive to them are destroyed. Viruses can be used along with other antibacterial agents, including to fight multiple-resistant microorganisms.
The study of two new bacterial viruses specifically infecting A. baumannii involved scientists from MIPT, the Institute of Antimicrobial Chemotherapy of Smolensk Medical University, the State Scientific Center for Applied Microbiology and Biotechnology, the Institute of Molecular Genetics and Gene Biology of the Russian Academy of Sciences, Skoltech, the Institute of Bioorganic Chemistry. Shemyakina-Ovchinnikova, St. Petersburg Medical University.
Anastasia Popova, an employee of the Laboratory for the Development of Innovative Medicines and Agrobiotechnologies of the MIPT Center for Living Systems, comments:
"In this work, two new bacteriophages vB_AbaP_AS11 and vB_AbaP_AS12 (AS11 and AS12) were isolated and characterized, which were assigned to the genus Fri1virus, subfamily Autographivirinae of the Podoviridae family. The lytic activity of bacteriophages was tested on 100 clinical antibiotic-resistant isolates of A.baumannii from 53 hospitals and 32 cities of Russia and Belarus. It was noted that these bacterial viruses are characterized by rapid adsorption to the bacterial host cell and a high yield of phage progeny per infected bacterial cell. The organization of genetic material (genomes) AS11 and AS12 was studied and the strategy of interaction of viruses with bacterial cells was described."
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30.08.2017