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Antibiotic resistance conferred by members of ARE subfamily of ABC proteins
Veselá, Ludmila ; Balíková Novotná, Gabriela (advisor) ; Borčin, Kateřina (referee)
The main topic of this thesis is the ARE subfamily of ABC transporters. The importance of the proteins of this subfamily lies in the fact that they confer resistance to several classes of clinically important antibiotics: macrolides, lincosamides, streptogramines and pleuromutilines and they do it in significant pathogens, as for example Staphylococcus aureus. Compared to canonical ABC transporters, the structure of ABC proteins lacks the transmembrane domain (TMD) and so far, there where not even found an integrating transmembrane protein. Due to these facts, the mechanism of resistance conferred by these proteins remains unclear. In the thesis, both suggested hypotheses of the mechanism of how these proteins work are discussed. The first hypothesis presumes the active efflux of antibiotics out of the bacteria. The second hypothesis suggests release of antibiotic from its binding site initiated by ARE proteins, followed by its passive diffusion out of the cell. Keywords: ABC proteins, ARE proteins, resistance, MLS, Vga
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Streptococcus agalactiae - antibiotic rezistence
Dvořáková, Andrea ; Voxová, Barbora (advisor) ; Janďourek, Ondřej (referee)
Streptococcus agalactie is an important pathogen causing very dangerous illnesses, especially in newborns. The aim of this work was to find out how resistant this microbe is to ATB (erythromycin, clindamycin, chloramphenicol, trimethoprim + sulfonamide, nitrofurantoin, penicillin, tetracycline, vancomycin and linezolid). At first testing was conducted on all watched group and subsequently on pregnant women and other patients. After the experimental stage, results from the pregnant women were compared with results from other tested group. In years 2018-2019, 1619 strains from 1295 patients in ÚKM FNHK were isolated. Sensitivity to ATB was measured in 1355 samples from 1105 patients. Within the all watched group of patients, resistance to each ATB was detected as follows: erythromycin (37,17 %), chloramphenicol (2,36 %), clindamycin (31,96 %), trimethoprim + sulfonamide (3,99 %), nitrofurantoin (1,11 %), peniciline (0,22 %), tetracycline (73,28 %) and to vancomycin and linezolid (0,00 %) of isolates. The resistance in pregnant women was detected as follows: erythromycin (26,36 %), chloramphenicol (2,33 %), clindamycin (22,87 %), trimethoprim + sulfonamide (3,49 %), nitrofurantoin (0,45 %), peniciline (0,39 %) and to tetracykcline (74,42 %) of isolates. After comparing results of resistance from...
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Characterization of the ABC-F protein Sco0636 in Streptomyces coelicolor
Pinďáková, Nikola ; Balíková Novotná, Gabriela (advisor) ; Mikušová, Gabriela (referee)
The main topic of this diploma thesis is ARE (resistance) proteins from the ABC-F family of the second class of ABC proteins. ARE proteins confer resistance to antibiotics that bind to a large ribosomal subunit and therefore inhibit proteosynthesis. One of the ARE proteins is the Lmr (C) protein, which is part of the linkomycin biosynthesis cluster of Streptomyces lincolnensis, and according to new results, Lmr (C) does not have to be just resistant protein but may have also regulatory function. We decided to study Sco0636, the closest homologue to Lmr (C) in Streptomyces coelicolor, which is a model organism in the study of secondary metabolism. Thanks to the production of color pigments, it is possible to monitor the effect of ARE proteins on secondary metabolism directly on the plates. I prepared the deletion mutant and the strain with constitutive expression of sco0636, and observed the effect on the phenotype. I followed the production of a blue asset and set a minimum inhibitory concentration to selected antibiotics, which bind to the ribosome. I have found that Sco0636 gives high resistance to tiamulin and so it has been named TiaA. The deletion of gene sco0636 accelerated production of actinorodine, and constitutive expression of this gene slowed down production. Keywords: ABC proteins,...
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Characterization of the ABC-F protein Sco0636 in Streptomyces coelicolor
Pinďáková, Nikola ; Balíková Novotná, Gabriela (advisor) ; Mikušová, Gabriela (referee)
The main topic of this diploma thesis is ARE (resistance) proteins from the ABC-F family of the second class of ABC proteins. ARE proteins confer resistance to antibiotics that bind to a large ribosomal subunit and therefore inhibit proteosynthesis. One of the ARE proteins is the Lmr (C) protein, which is part of the linkomycin biosynthesis cluster of Streptomyces lincolnensis, and according to new results, Lmr (C) does not have to be just resistant protein but may have also regulatory function. We decided to study Sco0636, the closest homologue to Lmr (C) in Streptomyces coelicolor, which is a model organism in the study of secondary metabolism. Thanks to the production of color pigments, it is possible to monitor the effect of ARE proteins on secondary metabolism directly on the plates. I prepared the deletion mutant and the strain with constitutive expression of sco0636, and observed the effect on the phenotype. I followed the production of a blue asset and set a minimum inhibitory concentration to selected antibiotics, which bind to the ribosome. I have found that Sco0636 gives high resistance to tiamulin and so it has been named TiaA. The deletion of gene sco0636 accelerated production of actinorodine, and constitutive expression of this gene slowed down production. Keywords: ABC proteins,...
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Development and genetic basis of glycopeptide resistance in coagulase-negative staphylococci
Prášilová, Jana ; Balíková Novotná, Gabriela (advisor) ; Lišková, Petra (referee)
Glycopeptides are the so-called last-resort antibiotics in clinical practice used to treat heavier, predominantly nosocomial infections caused by multi-resistant coagulase-negative staphylococci. The origin and genetic basis of resistance to glycopeptide antibiotics has not yet been elucidated within coagulase-negative staphylococci. Research on Staphylococcus aureus has shown, that intermediate resistance to glycopeptide antibiotics is associated with the presence of one or more mutations, rather than being conditioned by the support of a particular genetic element, such as in enterococci. By using various types of in vitro resistant mutant selection, we were able to obtain isogenic pairs of glycopeptide sensitive and resistant strains of Staphylococcus epidermidis and Staphylococcus haemolyticus. By sequencing the genomes of these pairs, one nucleotide polymorphisms were identified and predominantly found in metabolic and cell wall control systems. Phenotypic analysis did not reveal a direct association of glycopeptide resistance with increased biofilm formation. In clinical practice, the cross-resistance of glycopeptides and other antibiotics is problematic. For the non-glycopeptide antibiotics imipenem and rifampicin, the incidence of cross-resistance with glycopeptide antibiotics in S. aureus...
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Influence of expression of lmr(C) on the biosynthesis of lincomycin in Streptomyces lincolnensis: Resistance or production?
Veselá, Ludmila ; Balíková Novotná, Gabriela (advisor) ; Beranová, Jana (referee)
The genus Streptomyces produces more than a half of the known bioactive substances, ranking it among the most important bacterial taxons. Streptomyces lincolnensis ATCC 25466 encodes a biosynthetic gene cluster for lincomycin biosynthesis in its genome. Apart from the biosynthetic and regulatory genes, the cluster also contains three resistance genes, lmr(A), lmr(B) a lmr(C), which could protect of the host from the toxicity of a synthesized antibiotic. The Lmr(C) protein belongs to ARE proteins which generaly confer resistance to clinically important classes of antibiotics: macrolides, streptogramins, lincosamides and pleuromutilins. In addition to antibiotic producers, ARE proteins are also present in pathogenic microorganisms. However, the resistance mechanism conferred by these protins which belong to ABC transporters, even though they lack the transmembrane domain, have not been characterized yet. This makes the ARE proteins an interesting subject of the research. Using deletion mutants in resistance genes lmr(A), lmr(B) a lmr(C) we studied their effect on the lincomycin production and resistance to lincosamides, lincomycin and clindamycin with special focus on the function of the lmr(C). We have found that deletion of lmr(C) does not significantly influence lincomycin production and...
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Antibiotic resistance of Pseudomonas sp.
Gold, Lukáš ; Vejsová, Marcela (advisor) ; Voxová, Barbora (referee)
Lukáš Gold The resistance of Pseudomonas bacteria species to antibiotics Bachelor thesis Charles University in Prague, Faculty of Pharmacy in Hradec Kralove Medical laboratory technician This work was focused on summarising the basic knowledge on the resistance of Pseudomonas bacteria species to antibiotics, and the connection between their resistance and their diagnostics using new techniques, especially the mass spectrometry MALDI - TOF. As an introduction to this very extensive topic, we included a chapter on the general characteristics of Pseudomonas, in order to clarify the mechanisms by which resistance to antibiotics arise. Part of this review also includes laboratory diagnosis using conventional phenotypic methods as well as new techniques, mainly using the mass spectrometry MALDI - TOF. A small and yet considerably significant section of the work includes chapters on the infections caused by the Pseudomonas species and their recommended therapies. The position of the Pseudomonas species as one of the nosocomial pathogens is generally made mention of in this work. This review therefore, contains general information on Pseudomonas species that are related to their resistance to antibiotics, and mainly pertaining to their mechanisms of resistance and production of carbapenemases, which can be...
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The effect of vanZTei and vanZg expression on resistance to glycopeptide antibiotics in Staphylococcus aureus
Zieglerová, Leona ; Balíková Novotná, Gabriela (advisor) ; Lichá, Irena (referee)
A membrane protein VanZTei which is encoded by the gene vanZ from the vanA glycopeptide resistance gene cluster is a part of the large family of VanZ proteins. VanZTei confers resistance to teicoplanin in Enterococcus faecalis without the presence of other proteins encoded by the cluster. The aim of my work was to compare the ability of two orthologous proteins VanZTei and VanZg (from the genome of Enterococcus faecium) to confer resistance to glycopeptides in Staphylococcus aureus RN4220 and Enterococcus faecium. We have shown that VanZg increases resistance to teicoplanin (Tei) 8 to 16 times the and also to dalbavancin (Dalb) 8 times. VanZTei also confers resistance to Tei and Dalb, but the increase is only twofold. Conversely VanZTei confers resistance to newly synthetized glycopeptides more effectively than VanZg (fourfold increase of resistance confered by VanZTei and two to fourfold increase of resistance confered by VanZg). It suggests that both proteins have different specificity to antibiotics. In despite the mutants of S. aureus RN4220 VanZTei pRMC2 with increased resistance to teicoplanin (MICTei> 8 µg/ml) in which the resistance is dependent on vanZTei expression were selected. These resistant mutants do not carry mutation in a gene vanZTei or in its ribosomal binding site. Neither of the...
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Antibiotic resistance conferred by members of ARE subfamily of ABC proteins
Veselá, Ludmila ; Balíková Novotná, Gabriela (advisor) ; Borčin, Kateřina (referee)
The main topic of this thesis is the ARE subfamily of ABC transporters. The importance of the proteins of this subfamily lies in the fact that they confer resistance to several classes of clinically important antibiotics: macrolides, lincosamides, streptogramines and pleuromutilines and they do it in significant pathogens, as for example Staphylococcus aureus. Compared to canonical ABC transporters, the structure of ABC proteins lacks the transmembrane domain (TMD) and so far, there where not even found an integrating transmembrane protein. Due to these facts, the mechanism of resistance conferred by these proteins remains unclear. In the thesis, both suggested hypotheses of the mechanism of how these proteins work are discussed. The first hypothesis presumes the active efflux of antibiotics out of the bacteria. The second hypothesis suggests release of antibiotic from its binding site initiated by ARE proteins, followed by its passive diffusion out of the cell. Keywords: ABC proteins, ARE proteins, resistance, MLS, Vga
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