National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Glycopeptide resistance in staphylococci
Rozsypálková, Adéla ; Tkadlec, Jan (advisor) ; Balíková Novotná, Gabriela (referee)
The aim of this thesis is to describe the mechanism of the resistance to glycopeptide antibiotics in a genus Staphylococcus, especially in a species Staphylococcus aureus which is common cause of nosocomial infections resulting frequently in expensive and long-term treatment. This pathogen is dangerous due to its ability to acquire resistance to most antibiotics used in a clinical practice. The resistance of these microorganisms can develop very easily due to inappropriate treatment (administration, drug concentration, duration), which, if not detected, could ultimately results in treatment failure and the death of the patient. The vancomycin resistance of S. aureus could be divide into groups according to their values of vancomycin MIC: VSSA, VISA, hVISA and VRSA. Vancomycin intermediate resistance is associated with mutation, e.g., which affect cell wall synthesis. In contrast, VRSA is associated with the transfer of the mobile genetic element with the vanA or vanB operon from genus Enterococcus. This transmission is due to co-infection with both pathogens. Glycopeptide resistance has also been shown to be very common in coagulase-negative staphylococci (CNS), such as S. capitis, which cause infection in preterm infants. Glycopeptide resistance in CNS and intermediate resistance of S. aureus is...
Molecular analysis of resistance gene vga(A)LC identification of key aminoacid residues.
Kroová, Michaela ; Najmanová, Lucie (advisor) ; Vopálenský, Václav (referee)
Protein Vga(A) gives staphylococci resistance to streptogramins A. The recently discovered protein Vga(A)LC differs from Vga(A) only by 7 amino acid residues, but this difference is sufficient for shift of its substrate specificity towards lincosamides. The group of four amino acids in the central part of protein (LGAG in Vga(A) and SVTS in Vga(A)LC) was detected to be crucial for the substrate specificity. In this diploma thesis 5 alternativesets of vga(A)LC gene point mutations were prepared in order to determine the impact of individual amino acids of the aforementioned group on the resistance phenotype. Mutations were prepared in vector pGEM® -T and cloned into shuttle vector pRB374. The prepared constructs were transformed by electroporation into the sensitive strain of Staphylococcus aureus RN4220 and values of minimum inhibitory concentration (MIC) were measured for lincomycin, clindamycin and pristinamycin IIA by the agar dilution method. The transformation was not successful in one of the mutations. Results of setting MIC for the remaining four mutations do not make it possible to specify uniquely the ratio of individual amino acids for determining substrate specificity. Two of the amino acids were found to be important. We anticipate preparation of more mutations.

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