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30 Cards in this Set
- Front
- Back
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Trimethoprim is a competitive inhibitor of:
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Dihydrofolate reductase
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Trimethoprim has a _____ for the bacterial enzyme (high selectivity)
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High affinity
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Causes a rapid and complete inhibition of enzyme activity
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Trimethoprim
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Works in the folate pathway in both humans and bacteria, unlike sulfa
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Trimethoprim
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Trimethoprim has a _____ similar to the sulfonamides
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Spectrum of activity
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Trimethoprim is used in combo with sulfas to ______ folate metabolism
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Interfere with
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Trimethoprim is __________ in the same conditions as sulfas
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Bacteriostatic or bacteriocidal
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Increased levels of enzyme
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Basis for resistance to trimethoprim
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Reduced binding to trimethoprim
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Basis for resistance to trimethoprim
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PCN was discovered by ______ in _____
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Fleming; 1928
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Fleming discovered PCN as it inhibited the growth of:
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Staphylococcus cultures
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Derived from mold
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PCN
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PCN-ases break the ______ ring
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Beta-lactam
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Break down cell wall
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Autolysins
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_______ interfere with synthesis of new cell wall during growth stages
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PCN and cephalosporins
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Cell interior of gram positive bacteria is:
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Hypertonic
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High degree of _____ in the wall prevents membrane rupture
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Cross linking
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PCN inhibits ______ in cell walls units
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Cross linking
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New unit of cell wall is inhibited to linking with the pre-existing cell wall by:
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Vancomycin and bacitracin
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Production of cell wall building blocks inside the cell are inhibited by:
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Cycloserine
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Used primarily for TB
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Cycloserine
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Structure of _____ is similar to that of D-alanyl-D-alanyl terminus of polypeptide side chain of peptidoglycan
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PCN
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Lack of accessibility to target (gram negative bacteria)
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Basis for resistance to PCN
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Production of penicillinases (or beta lactamases)
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Basis for resistance to PCN
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Alterations in PCN binding proteins
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Basis for resistance to PCN
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Change in affinity; increased levels of other PBPs
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Alterations in PCN binding proteins
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Effects of PCN on a particular bacterium may be r/t the _______ that are affected
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PCN binding proteins
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Binding to PBPs 2 and 3=
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Prevents cell division (loss of rod like structure, filament formation)
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Binding to PBP 1 =
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Inhibits synthesis of cell wall (organisms undergo osmotic lysis)
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Gram Neg bacteria have an :
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Outer membrane
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