Question | Answer |
Aminoglycosides MOA | Passive diffusion, active transport(O2 required).Binds selectively to 30S or 50S ribosomal subunit. Intefere with protein synthesis-Block initation of tRNA, translation of mRNA. Possible increase in permibility due to gene alterations. |
Aminoglycosides spectrum of activity | ONLY aerobes mainly Gram - P aeruginosa, Acinobacter |
Aminoglycoside resistance | Plasmid mediated via modifying enzymes |
Aminoglycoside enzyme resistance rank | Amikacin> Tobra> genta |
Kanamycin | Used as a surgical irritant |
Streptomycin | TB treatment |
Alteration of B-Lactam nucleus causes | B-lactam inactivity |
Side chain of B-lactam | Increase stability, decrease excretion |
Extended spectrum Pen's | Penicillinase resistant, carboxypenicillins, Ureidopenicillins |
B-lactam MOA | PBP irreversible inhibition (transpeptidase) decrease cell synthesis and remodeling |
PBP acts to | Catalyze the transpeptidase rxn |
Natural penicillins ADME | Poor, extracellular no CNS, renal |
Natural spectrum of activity | Gram + aerobes Gram - Only Neissera, Not B. fragelis (syphillis) |
Penicilline resistant ADME | varies, nafcillin (IV)& hepatic |
Penicilline spectrum of activity | Gram + Staph Aureus, No enterococci |
Aminopenicillins ADME | Good, good, renal |
Aminopenicillins spectrum of activity | Created for gram - -excellent on lactose, H.influenza |
Carboxypenicillins spectrum of activity | GRAM + Staph aureus, Strep
Gram - Enteric bacilli, P. aeruginosa, H. inf |
Ureidopenicillins spectrum of activity | Great Gram + S. Auresu & Great Gram - lactose, P.aeruginosa, H. influenza |
Penicillins SE | GI, Rash (amoxicillin), Hematologic, CNS, electrolyte, increased LFT's |
PEN cross HYPERsen | 7-10% cephalosporins, carbapenems, rare Monobactams-aztreonam |
Carbapenems hypersensitivity | 100% with cephalosporins |
PEN monitoring | C. difficile, superinfection |
PEN DI | mixing with aminoglycosides, probenecid inhibits secretion |
B-lactamase and penicillinase inhibitors work in | anaerobic organisms, and Gram - aerobic bacilli |
1st generation cephalosporin | cefazolin, cephalexin |
2nd generation cephalosporings | cefaclor, cefuroximine,cefoxitin |
3rd generation cephalosporins | cefpodoxime, ceftrixone, ceftazidine |
4th generation cephalosporin | cefepime |
Cephalosporins ADME | good, well dist, renal |
cephalosporins have weak activity on | anerobics (except cefoxitin) |
1st generation spectrum of activity | Great gram + stable against B-lactams and penicilliniase |
2nd generation spectrum of activity | gram + ok, gram - lactose, H. influenza, moraxella |
3rd generation spectrum of activity | Great Gram - (lactose, H.I, mora) but inactivation by enzymes (ceftazidine)-P. aeruginosa) |
Ceftriaxone SE | hepatic sludging in neonates |
4th generation spectrum of activity | Awesome on Gram - P. aeruginosa, Gram + good similar to 1st generation |
4th generation ADME | best CNS penetration of cephalosporins |
cephalosporins hypersen | 1-3% occurance |
Carbapenems | Imipenenems, Ertapenem |
Carbapenem spectrum of activity | Gram - is AWESOME, enterobact, H.Inf, Mora, neisser, P. aeru, acinob. Anaerobic AWESOme |
Carbapenenem resistance | similar to B-lactams but less B-lactamase resistance, and loss of porins |
Probenecid causes inhibition of tubular secretion | Penicillins, cephalosporins, carbapenenems |
Monobactams | Azetreonam |
Azetronam spectrum of activity | Gram - P. aeruginosa |
Fluroroquinolones MOA | Topo II DNA gyrase(gram-) Topo IV (C,E) Gram + inhibited |
TOPO II (DNA gyrase) inhibition | Gram -bind part A, B site of ATP hydrolysis and DNA movement |
TOPO IV (C, E) inhibition | Prevents daughter chromasomes from segregating. |
Fluoroquinolone resistance | TOPO II (DNA gyrase mutation) or TOPO IV, efflux proteins 2 mutations needed |
Fluoroquinolone ADME | excellent, extensive, renal (moxi- hepatic) |
Ciprofloxacin activity | Gram - Awesome P.aeruginosa, Atypicals wow! (BID dosing) |
ceftriaxone t1/2 is | 8hrs and QD dosing |
Fluoroquinolone dosing is | QD (Cip-BID) (Moxi-13 hr) |
Fluoroquinolones are not active against | MRSA and enterococci |
Fluoroquinolone spectrum of activity | Gram - excellent, Gram+ good, anaerobic, Atypicals |
Fluoroquinolone DI | Antiacids, milk products, divalent cations, ferrous sulfates, p450s, theophylline, warfarin |
Vancomycin spectrum of activity | ONLY Gram + MRSA S. epidermis, coagulase negative staph, strep, enterococci (with PEN, AMP), Anaerobic, C. DIFF |
treats C. Diff | vancomycin |
Vancomycin MOA | High affinity binding for D-alanyl-D-alanine to block release and prevent cross linking |
Slow bacterialcidal | vancomycin |
Vancomycin resistance | Change of D-alanyl-D-alanine to D-alanyl-D-lactate and plasmid mediated MOA to interfere with transport into bacteria |
Vancomycin ADME | poor absorption, limited CNS, renal BID dosing |
Vancomycin SE | Nephrotoxic, ototoxic, Phlebis |
Vancomycin DI | Concommitantly with aminoglycosides |
Streptogramins- | Synercid- Quinupristin/dalfopristin |
Synercid spectrum of activity | Gram + MRSA and others , some atypicals |
Streptogramins MOA | Bind 50s ribosome to prevent elongation |
Streptogramins resistance | Plasmid mediated modification to binding 50s ribosome |
Oxazolidinones | Linezolid |
Bacteriostatic | either dalfopristin or quinupristin alone or linezolid |
Linezolid spectrum of activity | Gram + stapyh, strep, MSRA, S.epider, caogulas neg, E. faecalis and vancomycin resistant enterococci |
Linezolid MOA | Prevents the formation of tRNAm mRNA of 70s to block formation of the initiation comples (does not block elongation or termination) |
Linezolid DI | Competitive inhibitor of MAOA and MAOB, and serotoin syndrome reported. |
Synercid MOA | Binds 50s ribosome to prevent elongation |
Cyclic Lipopeptide | Daptomycin |
Daptomycin MOA | Rapid depolarization of cell membrane and efflux of potassium |
Daptomycin ADME | ok, low in respiratory due to surfactant inactivation |
Daptomycin SE | GI, HA, elevation of creatine phosphokinase (watch statins) |
PD | study of the relationship between concentration of drug and the response obtained by a patient |
PK | ADME useful for the prediction of serum concentration, CL, T1/2 |
Concentration dependant antibiotics | Fluoroquinolones, Aminoglycsides, Metronidazole, Ketolides |
Time dependant | B-lactams, cephalosporins, monobactams, carbapenems, vancomycin, azithromycin, macrolides, clindamycin |
Concentration dependant define | Comparision of concentation vs MIC studies as we increase concentration we increase bactericidal activity |
Time dependant antimicrobials | From Concentration and MIC studies we see killing activity is only marginally increased if concentration is increased above MIC, the PD relationship for these drugs is duration that con exceeds MIC. |
Time dependant goals | Time> MIC 50% or more |
Fluoroquinolone Concentration dependant goals Cmax/MIC | >10-12 correlates with favorable clinical and microbiological response |
Fluoroquinolone concentration goals AUC/MIC Gram - | 125-250 |
Fluoroquinolone concentration goals AUC/MIC Gram+ | > 30 |
Aminoglycoside ring structures | Aminocyclitol and 2-deoxystreptamine |
No cephalosporin has spectrum of acitivy against | MRSA, entercocci, listeria, or atypicals |