Resistance factors of bacterial nosocomial infections causative agents as background for the modern antimicrobials development
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Дата
2023
Автори
Науковий керівник
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Видавець
Igor Sikorsky Kyiv Polytechnic Institute
Анотація
Wu Lin. Resistance factors of bacterial nosocomial infections causative agents
as background for the modern antimicrobials development – qualification scientific
work on manuscript rights.
Thesis for the degree of Doctor of Philosophy in specialty 091 – Biology.
National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic
Institute", Kyiv, 2023.
The relevance of the research. The era of antibiotics, which began with the
discovery of penicillin in the ХХ century, may soon end and humanity will face a
challenge to overcome which will have to find new solutions. This challenge is now
the "era of antibiotic resistance", caused not only by evolutionary mechanisms of
protection of pathogens, but also by many factors of human activity.
Particular importance are methods of combating infectious agents when they
are in treatment centers and a large number of people can both become infected and
be a source of their spread. Such infections are nosocomial (hospital-acquired
infection) and are defined by World Organization of Health (WHO) as infections
that can infect the patient during treatment in hospital or other health care facilities.
The sources of infection in hospitals are not only other patients and staff, but also
surfaces, instruments, medical manipulations and operations, which is cause to
problems in ensuring proper conditions. However, one of the important factors in
the treatment of nosocomial infections is their resistance to many antibiotics used in
hospitals at the same time, and as a result “superbug” arise, for which there is no
effective counteraction. WHO defines a list of such relevant "superbugs", and almost
half of them are included in the already established acronym ESCAPE –
Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae,
Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.
It was found that the natural and induced variability of microorganisms that
cause inflammatory processes can lead to increased resistance to the action of
previously effective antiseptics due to the acquisition of resistance. In addition, the
selection of resistant forms of microbial pathogens, can cause low efficiency of
therapy, severe disease, long-term treatment or, in some cases, the inability to
overcome the infection at all. The mentioned and many other sources, citing WHO
and the Center for Disease Control (CDC, USA), state that the need to develop
effective antimicrobials against these and other nosocomial infections is a "need of
the hour".
Obviously, the solution of the problem of overcoming nosocomial infections
has many dimensions, including organizational, educational, medical and so on. But
these long-term strategies do not remove the urgent task of finding effective
antimicrobials or new combinations to treat these severe, often combined infections,
right today. This work currently involves a large number of scientists and
practitioners, with different approaches to the solvation of the problem. One of the
most effective method is undoubtedly the identification of the most vulnerable sites
of infectious agents and their application as targets for new drugs. Such vulnerable
points of microbial pathogens mainly determine their resistance and pathogenicity,
and therefore these factors should be considered more closely to find the target.
Therefore, the systematization of scientific data and results in this regard, the
analysis and evaluation of the main factors of pathogenicity and resistance of
nosocomial and other infections are relevant to determine modern approaches to the
development of the latest antimicrobial agents.
The goal of the work was to justify systemic approaches to the development
of modern antimicrobials based on the analysis of resistance factors of bacterial
pathogens of nosocomial infections.
To achieve the goal, it was necessary to solve the following problems:
- on the basis of theoretical analysis and research, determine the factors and
mechanisms of resistance of microbial pathogens, which can be chosen as targets for
the action of antiseptics;
- to establish the molecular-genetic characteristics of individual
representatives of bacterial pathogens that can be used to counter their distribution
and to select strategies for antimicrobial therapy;
- to propose a method of screening antimicrobial substances for selected
pathogenesis targets of pathogenic bacteria, which can be applied in research
practice;
- to show the prospects of creating effective antiseptics based on microbial
products - antibiotics and enzymes of the streptomycete Streptomyces albus;
- to develop recommendations for the implementation of methods of
monitoring the resistance of nosocomial infections and the principles of modern
antimicrobials development.
Scientific novelty of the obtained results.
The following scientific results were obtained for the first time in the
dissertation:
- on the basis of genome sequencing and gene annotation of the strain
Bacteroides thetaiotaomicron DSMZ 2079 isolated from the patient's blood, the
presence of a one- and two-component system for recognizing environmental signals
and responding to them was shown, the presence of four homologs of the selftransmitted conjugative transposon CTnDOT, which provides the extension of
resistance to tetracycline and erythromycin. The rpoB and tuf genes (in the
JHR92_RS03155 and JHR92_RS03195 loci, respectively), which determine the
strain's resistance to antibiotics, were identified;
- based on the results of the analysis of the 16S rRNA sequences of the isolated
clinical strain Pseudomonas oryzihabitans JN 873340 and its comparison with 29
other strains of the species from GenBank, a phylogenetic tree was built and the
possibility of identifying their geographical origin by two hypervariable regions V4
and V5 was shown;
- the minimum inhibitory concentrations of the new streptofungin antibiotic
against C. albicans ATCC 10231 (10 μg/ml), B. subtilis ATCC 6633 (200 μg/ml) and
P. aeruginosa ATCC 9027 (500 μg/ml) were established, as well as the absence of
toxicity in a wide range of concentrations (from 2.5 to 500 μg/ml), which determines
its potential as an active pharmaceutical ingredient;
Practical significance of the obtained results. The practical significance of
the dissertation consists in solving the scientific and practical problem of developing
antimicrobial agents that do not cause the resistance development of microbial
pathogens.
The developed method for screening inhibitors of sortase A, which is
distinguished by the use of cheaper substrates and, accordingly, the possibility of
wide application, has been implemented in the practice of the Environmental
Comprehensive laboratory of the School of Tropical Medicine of Hainan Medical
University, China. (Act of implementation dated September 4, 2023).
Developed "Recommendations for the implementation of methods of
resistance control of nosocomial infections and principles of development of modern
antimicrobial drugs", approved (08.25.23) at the Shupyk National Healthcare
University of Ukraine, for use in practice.
Proposed as a result of the dissertation research the principles and approaches
for the creation of preparations based on biologically active substances with different
mechanisms of action were used in the production program of LLC "PHARMA
INTERNATIONAL GROUP 2" (Kyiv) in the development of functional cosmetics
(Instructions for use dated 20.07.2023 r.).
The results of the work were implemented in the teaching of the courses
"General microbiology and virology" and "Fundamentals of pharmaceutical
production" for students of the specialty 162 "Biotechnology and bioengineering" at
the department of industrial biotechnology and biopharmacy of KPI named after Igor
Sikorskyi (Act of implementation dated 20.09.2023), as well as for students of the
specialty "Tropical medicine" within the framework of lectures and laboratory
(practical) classes in the disciplines "Medical immunology", "Pathobiology",
"Medical microbiology", "Environmental microbiology ", "Hygienic microbiology",
"Environment and health" at Hainan Medical University (China) (Act of
implementation dated 01.09.2023).
The main provisions of the work are presented in 10 scientific papers: 4
scientific articles included in the Scopus scientometric database, including 2 of them
in publications assigned to the 2nd quartile (Q2) in accordance with the SCImago
Journal and Country Rank classification (equal to two publications that are counted
in accordance with the first paragraph of paragraph 11 of the Resolution of the
Cabinet of Ministers of Ukraine dated March 6, 2019 No. 167); 4 articles in
specialized foreign periodicals; 2 abstracts at all-Ukrainian and international
conferences.
Опис
Ключові слова
infections, pathogens, antimicrobials, toxicity, resistance, enzymes, antibiotic
Бібліографічний опис
Wu Lin. Resistance factors of bacterial nosocomial infections causative agents as background for the modern antimicrobials development : thesis ... doctor of philosophy : 091 Biology / Wu Lin. – Kyiv, 2023. – 144 p.