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7 Cards in this Set
- Front
- Back
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How does the promotion of antibiotic efflux relate to tetracyclines?
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The primary mechanism for decreased accumulation of tetracycline is due mainly to active efflux of the antibiotic across the cell membrane.
decreased uptake of tetracycline from outside the cell also accounts for decreased accumulation of tetracycline inside resistant cells. |
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Tetracycline resistance genes are generally inducible by subtherapeutic concentrations of tetracycline which emphasizes the importance of adequate dosing. TRUE/FALSE
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TRUE. Pseudomonas aeruginosa and Staph. aureus display this type of resistance to tetracycline.
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Resistance to a wide variety of antiribosomal agents, including tetracyclines. macrolides, clindamicin and the aminoglycosides, may result from alteration of ribosomal binding sites. TRUE/FALSE
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TRUE.
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What is the concept behind alterations of cell wall precursor targets?
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Resistance of Enterococci to vancomycin has been classified as A, B, or C based on levels of resistance.
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What is Class A resistance?
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It is considered high level resistance and is associated with the VanA gene.
This gene is carried on a plasmid and encodes an inducible protein that is involved in cell wall synthesis in E. coli. |
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What are these inducible proteins used for?
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They are responsible for synthesizing peptidoglycan precursors that have a different amino acid sequence from the normal cell wall peptidoglycan. This newly modified peptidoglycan binds glycopeptide antibiotics with reduced affinity, thus leading to resistance to Vancomycin and teicoplanin.
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What do classes B and C do?
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These resistance phenotypes are considered to have moderate and low level resistance respectively.
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