Antibiotics Flashcards
What does it mean when an antibiotic is antiseptic?
Kills and inhibits organisms on the body
What is a disinfectant?
Kills and inhibits organisms on inanimate objects
What is the definition of sterilization?
All organisms are killed
What are the 2 MC antiseptics used in surgery?
Iodophors (Betadine) and chlorhexadine gluconate
Betadine is good for what organism coverage?
GPCs and GNRs; poor for fungi
Chlorhexadine is good for what organism coverage?
GPCs, GNRs, and fungi
What classes of antibiotics are inhibitors of cell wall synthesis?
Penicillin, cephalosporins, carbapenems, monobactams, vancomycin
What classes of antibiotics are inhibitors of 30s ribosome and protein synthesis?
Tetracycline, aminoglycosides (tobramycin, gentamicin), and linezolid
What classes of antibiotics are inhibitors of the 50s ribosome and protein synthesis?
Erythromycin, clindamycin, Synercid
What is the MOA of quinolones?
Inhibitor of DNA helicase (DNA gyrase)
What is the MOA of rifampin?
Inhibitor of RNA polymerase
What is the MOA of Flagyl (metronidazole)?
Produces oxygen radicals that break up DNA
What is the MOA of sulfonamides?
PABA analogue which inhibits purine synthesis
What is the MOA of trimethoprim?
Inhibits dehydrogenase reductase, which inhibits purine synthesis
What class of antibiotics are bactericidal? Why?
Aminoglycosides. Bind irreversibly to ribosome
What classes of antibiotics are bacteriostatic? Why?
Tetracyclines, clindamycin, erythromycin — all bind reversibly to ribosome
What is the mechanism for resistance to penicillins?
Due to plasmids for beta-lactamase (staph aureus)
What is the MC method of antibiotic resistance?
Transfer of plasmids
What is the mechanism of resistance of MRSA?
Mutation in cell wall binding protein
What is the mechanism of resistance in vancomycin resistant enterococcus (VRE)?
Mutation in cell wall binding protein
What causes gentamicin resistance?
Due to modifying enzymes leading to a decrease in active transport of gentamicin into bacteria
What is the appropriate peak levels of vancomycin?
20-40 ug/ml
What is the appropriate trough level for vancomycin?
5-10 ug/ml
What is the appropriate peak drug level of gentamicin?
6-10 ug/ml
What is the appropriate trough for gentamicin?
<1 ug/ml
What do you do if the peak level of a drug is too high?
Decrease the amount of each dose
What do you do if the trough level of a drug is too high?
Decrease frequency of doses (increase time interval between doses)
What organisms does penicillin cover?
Strep, syphilis, Neisseriea meningitides, Clostridium perfringens, beta-hemolytic strep, anthrax
NOT EFFECTIVE AGAINST STAPH OR ENTEROCOCCUS
What specific penicillin antibiotics cover staph?
Oxacillin, methicillin, and nafcillin -staph only
What is the difference between ampicillin & amoxicillin and other penicillin antibiotics?
These 2 also cover enterococci
What drugs make up unasyn?
Ampicillin and sulbactam
What drugs make up Augmentin?
Amoxicillin and clavulanic acid
What classes of organisms do Unasyn and Augmentin cover? Do not cover?
GPCs (staph and strep), GNRs, +/- anaerobic coverage
Effective for enterococcus
Not effective for pseudomonas, Acinetobacter, or serratia
What is the MOA of sulbactam and clavulanic acid?
Beta-lactamase inhibitors
What penicillins cover pseudomonas? What other bacteria do they cover?
Ticarcillin and piperacillin
GNRs-enterics, Acinetobacter, Serratia
What are the side effects of ticarcillin and pipercillin?
Inhibits platelets and high salt load
