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[h] Microbiology & Antimicrobials Flashcards
[i] Master this session in just 5 minutes.
[q] ………. are structural analogs of D-Ala-D-Ala that bind penicillin-binding proteins (transpeptidases) and inhibit it by binding covalently to its active site. The result is failed synthesis of the bacterial peptidoglycan cell wall. The weakened cell wall integrity causes osmotic lysis of the bacterium.
[c]IFNob3cgbWUgdG hlIGFuc3dlcg==[Qq]
[f]IEJldGEgbGFjdGFtIGFudGliaW90aWNzIChQZW5pY2lsbGlucywgQ2VwaGFsb3Nwb3JpbnMsIHBlbmVtcywgTW9ub2JhY3RhbXMpLg==[Qq]
[q] ………… are beta-lactamase resistant penicillins because bulky R group blocks access of β-lactamase to β-lactam ring. Reliable for treatment of known or suspected S. aureus (except MRSA; resistant because of altered penicillin-binding protein target site).
[c]IFNob3cgbWUgdG hlIGFuc3dlcg==[Qq]
[f]IFZlcnkgbmFycm93IHNwZWN0cnVtIHBlbmljaWxsaW4gKG1ldGhpY2lsbGluLCBuYWZjaWxsaW4sIG94YWNpbGxpbiwgY2xveGFjaWxsaW4sIGRpY2xveGFjaWxsaW4pLg==[Qq]
[q] ……… are Beta-lactamase sensitive penicillins. Mostly used for gram-positive organisms (S. pneumoniae, S. pyogenes, Actinomyces). Also used for gram-negative cocci (mainly N. meningitidis) and spirochetes (namely T. pallidum).
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[f]IE5hcnJvdyBzcGVjdHJ1bSBwZW5pY2lsbGluIChQZW5pY2lsbGluIEcgLCBwZW5pY2lsbGluIFYpLg==[Qq]
[q] …….. are Beta-lactamase sensitive penicillins, also combine with clavulanic acid to protect against destruction by β-lactamase. Have wider spectrum, gram-positive cocci (not staph), E. coli, H. influenzae, Listeria monocytogenes (ampicillin), Borrelia burgdorferi (amoxicillin), H. pylori (amoxicillin).
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[f]IEJyb2FkIHNwZWN0cnVtIEFtaW5vcGVuaWNpbGxpbnMgKGFtcGljaWxsaW4gYW5kIGFtb3hpY2lsbGluKS4=[Qq]
[q] …….. are Antipseudomonal, beta-lactamase sensitive penicillins. Have increased activity against gram-negative rods, including Pseudomonas aeruginosa.
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[f]IEV4dGVuZGVkIHNwZWN0cnVtIHBlbmljaWxsaW4gKFBpcGVyYWNpbGxpbiwgdGljYXJjaWxsaW4pLg==[Qq]
[q] β-lactamase inhibitors include ……… and …….?
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[f]IENsYXZ1bGFuaWMgQWNpZCwgU3VsYmFjdGFtLCBhbmQgVGF6b2JhY3RhbSAoQ0FTVCku[Qq]
[q] Which generation of cephalosporins?
– Spectrum: gram-positive cocci (not MRSA), Proteus mirabilis, E. coli, Klebsiella pneumoniae (PEcK).
– None enter CNS.
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[f]IEZpcnN0IGdlbmVyYXRpb24gKENlZmF6b2xpbiwgY2VwaGFsZXhpbiku[Qq]
[q] Which generation of cephalosporins?
– Spectrum: gram-positive cocci, Haemophilus influenzae, Enterobacter aerogenes, Neisseria spp, Serratia marcescens, Proteus mirabilis, E. coli, Klebsiella pneumoniae (HENS PEcK).
– None enter the CNS, except cefuroxime.
[c]IFNob3cgbWUgdG hlIGFuc3dlcg==[Qq]
[f]IFNlY29uZCBnZW5lcmF0aW9uIChjZWZhY2xvciwgY2Vmb3hpdGluLCBjZWZ1cm94aW1lLCBjZWZvdGV0YW4pLg==[Qq]
[q] Which generation of cephalosporins?
– Spectrum: gram-positive and gram-negative cocci, serious gram-negative infections resistant to other β-lactams.
– Ceftazidime has antipseudomonal activity.
– Most enter CNS; important in empiric management of meningitis and sepsis.
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[f]IFRoaXJkIGdlbmVyYXRpb24gKENlZnRyaWF4b25lLCBjZWZvdGF4aW1lLCBjZWZ0YXppZGltZSBhbmQgY2VmaXhpbWUpLg==[Qq]
[q] Which generation of cephalosporins?
– Spectrum: gram-negative organisms, with activity against Pseudomonas and gram-positive organisms.
– Resistant to most beta-lactamases.
– Enters CNS.
[c]IFNob3cgbWUgdG hlIGFuc3dlcg==[Qq]
[f]IEZvdXJ0aCBnZW5lcmF0aW9uIChDZWZlcGltZSku[Qq]
[q] Which generation of cephalosporins?
– Spectrum: broad gram-positive and gram-negative organism coverage.
– Unlike 1st-4th generation cephalosporins, it covers MRSA, and Enterococcus faecalis.
– Does not cover Pseudomonas.
[c]IFNob3cgbWUgdG hlIGFuc3dlcg==[Qq]
[f]IEZpZnRoIGdlbmVyYXRpb24gKENlZnRhcm9saW5lKS4=[Qq]
[q] In case of penicillin allergy, If there is rash to penicillin —> use …………, if there is anaphylaxis to penicillin —> use …….?
[c]IFNob3cgbWUgdG hlIGFuc3dlcg==[Qq]
[f]IGNlcGhhbG9zcG9yaW4sIG5vbi1CIGxhY3RhbSAoZm9yIGdyYW0tcG9zaXRpdmUgb3JnYW5pc21zLCBjb25zaWRlciBtYWNyb2xpZGVzOyBmb3IgZ3JhbS1uZWdhdGl2ZSByb2RzLCBjb25zaWRlciBhbWlub2dseWNvc2lkZXMgb3IgYXp0cmVvbmFtIGluIGNhc2Ugb2YgcmVuYWwgaW1wYWlybWVudCku[Qq]
[q] Mechanism of resistance to ……. is change in the structure of penicillin-binding proteins that prevents cephalosporin binding is one mechanism of bacterial resistance to cephalosporins.
[c]IFNob3cgbWUgdG hlIGFuc3dlcg==[Qq]
[f]IEJldGEgbGFjdGFtIGFudGliaW90aWNzLg==[Qq]
[q] ……. is broad spectrum antibiotics that cover Gram-positive cocci, gram-negative rods (Enterobacter, Pseudomonas spp.), and anaerobes. Resistant to beta-lactamases. Important in-hospital agents for empiric use in severe life-threatening infections. Given with cilastatin, a renal dehydropeptidase inhibitor, which inhibits imipenems metabolism to a nephrotoxic metabolite. Cause seizure as a side effect.
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[f]IEltaXBlbmVtLg==[Qq]
[q] ……….. effective against Gram-negative rods only, no activity against gram positives or anaerobes. For penicillin-allergic patients and those with renal insufficiency who cannot tolerate aminoglycosides. No cross-allergenicity with penicillins or cephalosporins.
[c]IFNob3cgbWUgdG hlIGFuc3dlcg==[Qq]
[f]IEF6dHJlb25hbS4=[Qq]
[q] ……….. Inhibits cell wall peptidoglycan formation by binding D-ala D-ala portion of cell wall precursors. Effective against Gram-positive bugs only, and serious, multidrug-resistant organisms, including (MRSA, Enterococci). Clostridium difficile (oral dose for pseudomembranous colitis). Side effects include: Nephrotoxicity, Ototoxicity, Thrombophlebitis, diffuse flushing “red man syndrome” due to histamine release with rapid IV injection (can largely prevent by pretreatment with antihistamines and slow infusion rate).
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[f]IFZhbmNvbXljaW4u[Qq]
[q] The mechanism of …… resistance in organisms such as VRE is a substitution of D-lactate in the place of D-alanine during the process of peptidoglycan cell wall synthesis. This prevents the binding of the drug to its usual D-alanine-D-alanine binding site in the cell wall.
[c]IFNob3cgbWUgdG hlIGFuc3dlcg==[Qq]
[f]IHZhbmNvbXljaW4u[Qq]
[q] ……………. is a lipopeptide antibiotic with activity toward Gram-positive organisms including MRSA, it works by disrupting the bacterial membrane through the creation of transmembrane channels. These channels cause leakage of intracellular ions leading to depolarization of the cellular membrane and inhibition of macromolecular (DNA, RNA, and protein) synthesis, which ultimately leads to cell death.
[c]IFNob3cgbWUgdG hlIGFuc3dlcg==[Qq]
[f]IERhcHRvbXljaW4u[Qq]
[q] ……. is not used in case of pneumonia because it is inactivated by pulmonary surfactant. Associated with increased CPK levels and an increased incidence of myopathy, particularly in patients using other drugs associated with myopathy (statins).
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[f]IERhcHRvbXljaW4u[Qq]
[x][restart]
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