Antimicrobials Flashcards
Minimum inhibitory concentration (MIC)
stops growth
Minimum bactericidal concentration (MBC)
kills 99%
bacteriostatic vs
bacteriocidal
stops growth/reproduction of bacteria
Kills bacteria directly
Broad spectrum antimicrobials
- Chloramphenicol
- Tetracycline
- Sulfonamides
- Trimethoprim
*assume everything else is narrow if it isnt also on extended antimicrobials list
Extended use antimicrobials
- Aminoglycosides
- Macrolides
- Streptogramins
- Extended spec- PCNs
- Cephalosporins
- Carbapenems
- FQ
*assume everything else is narrow if it isnt also on broad spect. antimicrobials list
Cell wall synthesis inhibitors
- B lactams
- PCNs, Cephalo, Carbapen, Monobactams - Glycopeptides
- Bacitracin
- Vancomycin - Cycloserine (TB)
Penicillins
- MOA
- Pharmacokinetics (excretion)
- Adverse rxn
MOA: Inhibit cell wall synth, bactericidal
Pharmacokinetics:
Renal excretion
Adverse:
Anaphylaxis (Type I)
Rash (Type III)
Convulsions at high dose
Which of the PCNs are good oral and which good IV?
All are good oral except:
- PCN G (IV/IM)
- Anti-pseudomonal (IV)
- Piperacillin (B lactamase inhib)
All rest are good oral
- Pen V
- PCNase resistant
- Methicillin
- Oxacillin - Extended spectrum
- Ampicillin
- Amoxicillin (w/ B lactam inhib)
Which are harder to treat? Gram - or Gram +?
Gram - : thin cell wall
- like a thin bullet proof vest - diff to penetrate
(Gram + have thick cw: like thick dry wall which absorbs more)
Spectrum/Uses (targets) of:
Pen G
Pen V
Gram +/- cocci,
Gram + bacilli, most anaerobes
Spectrum/Uses (targets) of:
Penicillinase resistant PCNs
B-lactamase producing S. aureus
Spectrum/Uses (targets) of:
Extended spectrum PCNs
Now PCN can target Gram -
*ie: enterobacteriaceae, H. flu, E. coli
Spectrum/Uses (targets) of:
Antipseudomonal (PCN)
Less Gram + (like nl PCN) and more Gram -
- remember gram - are harder to treat
- Ie: pseudomonas, bacteroides
List Cephalosporins (182)
1st gen:
2nd gen:
3rd gen:
1st gen:
- Cefazolin, Cephalexin
2nd gen:
- Cefoxitin, Cefaclor, Cefuroxime
3rd gen:
- Ceftriaxone, Cefoxatime, ceftazidime
4th:
- Cefipine
5th:
- Ceftaroline
Pharmacokinetics of Cephalosporins
- which one can distribute well to CSF?
Most IV, some po
3rd gen distributes well to CSF
- Ceftriaxone, cefoxatime, ceftazidime
Protein synthesis inhibitors
- Cloramphenicol
- Clindamycin
- Oxazolidinones*
- Linezolid - Macrolides
- Streptogramins**
- AG
- TCN
- Rhupirocin
Which protein synthesis inhibitors target 30s and which at 50s bacterial subunit? (leaving hu 80s unaffected)
buy AT 30, CCEL at 50
(184)
30s:
Aminoglycosides (cidal)
Tetracycline (static)
50s: Chloramphenicol Clindamycin (cidal) Erythromycin (static) Linezolid
List aminoglycosides
(184) “mean” for ameanoglycoside
mean GNATS
Gentamycin Neomycin Amikacin Tobramycin Streptomycin
Toxicity for aminoglycosides
(184) “mean” GNATS caNNOT kill anaerobes
Nephrotoxicity
Neuromuscular block
Ototoxicity (esp with loop diuretic)
Teratogen
Spectrum of Aminoglycosides
Med spectrum Gram - aerobes
TB
All protein synthesis inhibitors have GOOD po and IV pharmacokinetics, except ____ which is only good po, and _____ which is only good IV
Tetracycline: good po
- renal/biliary excret
Streptogramins: IV only
- hepatic elim
Tetracycline (TCN, doxycycline, minocycline) toxicity
- GI distress (interacts with metal ions in antacids/milk)
- Discoloration of teeth and inhibit bone growth in children (bone distribution)
- Photosensitivity
- Fungal Superinfections
Spectrum/use of tetracyclines
drugs ability to accumulate intracellularly makes them very effective against Rikettsia and Chalmydia
- Rikettsia
- Chlamydia
- Borrelia (spirochete)
- M. pneumonia
Pharmacokinetic of macrolides
Good PO + IV
- Concetrates in lungs
- Hepatic metabolism to active metabolite
- Biliary elim
MOA of macrolides
Macrolides block macroSLIDES
- bind to 23S rRNA of the 50s subunit and inhibit protein synthesis
Toxicity of macrolides
MACRO toxicity for macrolides
Motility issues (GI) Arrythmia Cholestatic hepatitis Rash eOsiniphilia
Drug interactions due to inhibition of P450
CLinical use of macrolides
atypical pneumonias
- Mycoplasma
- Chlamydia
- Legionella
STIs
- chlamydia
GPC
- streptococcal infxn in pts allergic to PCN
B. pertussis
Chloramphenicol clinical use
Broad spectrum
- Meningitis
- H. flu
- N. meningitidis
- S. pneumoniae - Rocky Mt spotted fever
- Rikettsia rikettsii
Chloramphenicol toxicity
- Anemia (dose dep)
- aplastic anemia
- gray baby syndrome
- in premature infants bc they lack liver UDP glucuronyl transferase
Chloramphenicol pharmacokin
Good PO, IV, distrib (CNS/CSF)
Metabolized via glucuronidation
*gray baby syndrome can result in premature infants
Clindamycin (185)
Pharmacokinetics
Good PO and IV
(Like most protein synthesis inhibitors)
Penetrates into bone
Hepatic metabolism
(treats anaerobic infxns above the diaphragm vs metronidazole which tx below)
Clindamycin (185) adverse rxns
Pseudomembranous colitis (c. diff overgrowth)
Fever, severe diarrhea
Clinical use of Clindamycin
Narrow spectrum
- Oral infxn
- Anaerobic infections in aspiration pneumonia
- Bacteroides, C. perfringens - Lung abscesses
- invasive GAS (gram +) **
Which two groups of Protein synth inhibitors can cover Vanco resistant Enterococcus faecium (VREF)?
Streptogramins
- Synercid
Oxazolidinones
- Linezolid
*both inhibit at 50s subunit
MOA and Pharmacokinetic of Streptogramins (pristins) and Oxazolidinones (linezolid)
protein synth at 50s subunit
IV
*linezolid can give good PO too
Adverse rxns of streptogramins
Inhibits CytP450
- increase plasma lvl of drugs
Adverse rxns of oxazolidinones
Serotonin Syndrome: - HA - D/N (gastro) Inhibits MAO - muscle rigidity - seizure
Peripheral neuropathy
Bone marrow suppression
Which antimicrobial agent to use against G+ species INCLUDING MRSA and VRE
Oxazolidinones
- Linezolid
