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What's the mechanism of action of Penicillin?
Block cell wall synthesis by inhibition of peptidoglycan cross-linking
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What's the mechanism of action of beta-lactams?
Block cell wall synthesis by inhibition of peptidoglycan cross linking.
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What's the mechanism of action of glycopeptides?
Block peptidoglycan synthesis.
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What's the mechanism of action of cephalosporins?
Block cell wall synthesis by inhibition of peptidoglycan cross-linking
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What's the mechanism of action of carbecephams?
Block cell wall synthesis by inhibition of peptidoglycan cross-linking
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What's the mechanism of action of lipopeptides?
Intereference of cell membrane potential.
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What's the mechanism of action of polymixins?
Disruptio nof bacterial cell membranes.
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What's the mechanism of action of oxazoladinones (linezolid)?
Block protein synthesis at 50S ribosomal subunit.
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What's the mechanism of action of tetracyclines?
Block protein synthesis at 30S ribosomal subunit.
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What's the mechanism of action of aminoglycosides?
Block protein synthesis at 30S ribosomal subunit.
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What's the mechanism of action of chloramphenicol?
Block protein synthesis at 50S ribosomal subunit.
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What's the mechanism of action of lincosamines?
Block protein synthesis at 50S ribosomal subunit.
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What's the mechanism of action of macrolides?
Block protein synthesis at 50S ribosomal subunit.
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What's the mechanism of action of type B streptogramins?
Block protein synthesis at 50S ribosomal subunit.
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What's the mechanism of action of ketolides?
Block protein synthesis by binding to ribosomal subunits and may also inhibit the formation of newly forming ribosomes
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What's the mechanism of action of sulfonamides?
Block nucleotide synthesis.
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What's the mechanism of action of trimethoprim?
Block nucleotide synthesis.
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What's the mechanism of action of fluoroquinilones?
Block DNA topoisomerases.
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What's the mechanism of action of nitromidazole?
Metronidazole metabolites are taken up into bacterial DNA, and form unstable molecules
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What's the mechanism of action of rifamycin?
Binds to RNA polymerase to prevent RNA synthesis.
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Minimum inhibitory concentration - (MIC)
lowest concentration that inhibits growth after 18-24 h in vitro
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Minimum bactericidal concentration - (MBC)
lowest concentration at which 99.9% of a culture is killed after18-24 h incubation in vitro
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Post-antibiotic effect (PAE)
when suppression of bacterial growth continues after the antibioticconcentration falls below the bacterial MIC
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Concentration-dependent killing
bactericidal effects increase with increased concentration of antibiotic
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Time-dependent killing
bactericidal effects occur only during the time when the antibiotic is maintainedabove the MIC
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Superinfection
a second “opportunistic” infection occurring during the course of antimicrobial therapy,can be due in part to loss of normal oral or gut flora
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Protein binding
protein binding varies greatly among the different antibiotics; binding in the plasma is asaturatable process; only the protein-free antibiotic can have antimicrobial activity
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What enzyme is targeted in the inhibition of proteoglycan synthesis?
- Transglycosylase
- (vancomyocin, teicoplanin)
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What enzyme is targeted in the inhibition of proteoglycan cross-linking?
- Transpeptidase - D-alanyl-D-alanine analogue substrate
- (β-lactams, penicillins, cephalosporins, monobactams, carbepenems, carbacephem)
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What are the mechanisms of action of b-lactams?
- Covalent binding of D-ala-D-ala to transpeptidase
- Binding to Penicillin binding proteins
- Activate autolyic enzymes that break down cell wall
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What are the mechanisms ofor restance for b-lactams?
- Penicillinases
- Decreased affinity of PBPs
- Decreased membrane permeability
- Efflux pumps
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What are adverse effects of b-Lactams?
Hypersensitivity, Diarrrhea (young), CV fluid overload, CNS effects (renal failure), coagulation defects
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Where are penicillins distributed to?
Everywhere but CSF
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What's the metabolism/elimination of penicillins?
Renal secretion of unmetabolized drug
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What are the natural penicillins and their routes of ?
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