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42 Cards in this Set
- Front
- Back
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What do plasma membrane penicillin binding proteins do
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peptidoglycan cross-linking
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Generalizations for cell wall synthesis inhibitors:
-inhibit which more --> G+ or -G- -type of spectrum -cidal or static -ability to cross BBB -administration/clearance |
-G+ > G-
-narrow and extended spectrum -bactericidal -poor penetration of BBB -oral administration, renal clearance |
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What is fosfomycin
-spectrum type |
-structural analog of PEP
-broad spectrum |
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What is D-cycloserine
-penetration -spectrum -primary use |
-competitive inhibitor of cell wall synthesis (similar to D-alanine)
-good CNS penetration = CNS toxicity -broad spectrum -second=line tb drug b/c it's so toxic |
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How does bacitracin work?
-what is its application -what is it used for |
-depletes lipid carrier for synthesis of peptidoglycan
-topical application only b/c of toxicity -skin and eye uses |
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How does vancomycin work?
-administration -adverse effects -active against? |
-blocks transpetidation by binding the substrate
-IV administration -lots of adverse effects - red man syndrome, ototoxicity -gram + and MRSA |
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How do bacteria become resistant to vancomycin?
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van A, B, or C gene encodes for peptide with D-ala-D-lactate or D-ala-D-serine = reduced affinity for drug
-Staph can over express D-ala-D-ala = competes to bind up drug |
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Generalizations for B-lactams:
-block what? -administration -adverse effects -cidal/static |
-block transpeptidation
-various routes of administration, renal clearance, not metabolized -allergic response -cidal for gram + |
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How do B-lactams work?
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-structural analog of terminal D-ala-D-ala so bind to PBP and competitively block activity
-prevent formation of cell wall = cidal |
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What must be happening for B-lactams to work
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bacteria must be synthesizing cell walls
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How do the different R groups change b-lactam properties
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acid stability, binding to plasma proteins, anti-bacterial spectrum, resistance to b-lactamase
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What are four mechanisms of bacterial resistance to b-lactams
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-production of b-lactamases
-alter target PBPs = decrease affinity for B-lactam -alter outer membrane to prevent drug from reaching PBP -efflux pumps to transport b-lactams to outside of bacterial outer membrane |
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T/F - B-lactams are irritating to tissues and can cause phlebitis when given IV
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-true
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What type of allergic reaction is 80-90% of penicillin reactions
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delayed rection - 2 or more days after administration, mild, reversible rash
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Which groups of penicillins are sensitive to penicillinase
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group 1 and 3
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List types of penicillins of groups 1, 2, and 3
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1 - penicillin G and V
2 - anti-staph penicillin 3 - extended spectrum -amino, carboxy, ureido penicillins |
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What is the spectrum of penicillins in groups 1, 2, and 3
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1 - narrow spectrum
2 - penG spectrum and staph that produce penicillinase 3 - extended spectrum, but NOT staph |
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What is the absorption of pen G, pen V, and procaine/benzathine pen G?
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pen G - acid labile, parenterally
pen V - acid stable (oral) pro/ben penG - water insoluble, IM |
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What is an adverse effect of pen G?
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dose-dependent neurotoxicity and seizures
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T/F - penicillin can cause stevens-johnson syndrome
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-true
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T/F - group 2 penicillins are active against gram -
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-false
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How does bacteria become resistant to group 2 penicillins
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-via methicillin due to PBP wit hlowered affinity for B-lactams
-won't work against MRSA |
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Which group 2 penicillin is acid stable?
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-oxacillin
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what is the major therapeutic use of group 2 penicillins
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-tx of infections caused by penicillinase-producing straings of staph
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What are adverse effects of methicillin and oxacillin
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meth - interstitial nephritis
oxacilin - hepatitis at high doses |
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Which two types of extended-spectrum penicillins are anti-pseudomonal
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carboxy penicillins and ureidopenicillins
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How is bacterial resistance caused in extended-spectrum penicillins
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increased production of penicillinases
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What is the absorption of amino penicillins and carboxy penicillins
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amino - stable in acid and well-absorbed orally
carboxy - not well absorbed from GI |
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What are amino penicillins used for
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-tx Gm neg infections
-tx of mixed infections -prophylaxis of SBE (amoxicillin) |
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What are carboxy penicillins and ureidopenicillins used for
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carboxy - rarely used alone
ureido - life-threatening infections caused by klebsiella and pseudomonas |
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What are the extended spectrum penicillin adverse effects
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allergy
super-infections aminopenicillin rash |
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How do augmented penicillins work
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extended-spectrum penicillin + b-lactamase inhibitor prevents inactivation of penicillin by overcoming penicillinase production
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T/F - b-lactamase inhibitors have good antibiotic activity
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-false
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What three ways do cephalosporins resemble penicillins
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-chemically
-mechanism of action -adverse effects |
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Trends from first to fourth cephalosporin generation:
-activity to Gm - and + -stability against b-lactamase -activity against staph -anti-pseudomonal activity -CNS penetration |
-Gm neg increases, Gm + decreases
-stability to B-lac improves -activity against staph decreases -anti-pseudomonal increases -CNS penetration increases |
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Which generation has broadest spectrum of activity against Gm + cocci
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1st generation
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What are the trends in acid stability for each generation
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1st gen is acid-stable (oral), rest are effective only when given IV or IM
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What are the adverse effects of cephalosporins
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-hypersensitivity, cross-allergenic
-some cause disulfiram-like rxn |
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What is the antibacterial activity and spectrum of carbapenems
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-interact efficiently with PBPs
-more effective against Gm- -broadest spectrum of activity |
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Carbapenems --> imipenem is metabolized how
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inactivated by dehydropeptidases in kidney, so administered with cilastatin to maintain MLC in urine
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What are the narrowest spectrum of activity of b-lactams
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monobactams
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What is a great thing about daptomycin - a cell membrane active agent
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can be used to tx VRE and MRSA
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