Antibiotic Therapy Flashcards
Mechanism of action of glycopeptides
Inhibition of bacterial cell wall synthesis. Work at an earlier stage than do beta-lactams.
Vancomycin is a “BLANK”
Glycopeptide
Daptomycin is a “BLANK”
Lipopeptide
Mechanism of action of Lipopeptides
Disruption of cell wall.
- Calcium dependent
- Depolarizes cell membrane
- Disrupts RNA, DNA, protein synthesis –> cell death
In general, Glycopeptides/Lipopeptides are active against:
Gram +ve organisms, including beta-lactam resistant organisms (i.e. MRSA)
Are Glycopeptides/Lipopeptides bacteriostatic or bactericidal?
Bactericidal
This Glycopeptide is slowly cidal, and when given PO is not systemically absorbed
Vancomycin
Lung surfactant inactivates “BLANK”; therefore, this agent should not be used to treat pneumonia!
Daptomycin
Spectrum and indications for Vancomycin IV
Spectrum: Gram +ve (Enterococci, penicillin resistant Streptococci, MRSA, CNS
Indications: Bacteremia, pneumonia, endocarditis, bone/joint, SSTI, surgical prophylaxis
Spectrum and indications for Vancomycin PO
Spectrum: C. difficile
Indications: C. difficile infection
Spectrum and indications for Daptomycin IV
Spectrum: Gram +ve (Enterococci, penicillin-resistant Streptococci, MRSA, CNS, and VRE)
Indications: Bacteremia, endocarditis, bone/joint, SSTI
Gentamycin and Tobramycin are both “BLANKS”
Aminoglycosides
Mechanism of action for Aminoglycosides
Inhibit protein synthesis by binding the 30S ribosomal subunit
Are Aminoglycosides bacteriostatic or bactericidal?
Bactericidal
Aminoglycosides are renally excretable and may cause the following toxicities (2)
- Nephrotoxicity
2. Ototoxicity
Gentamicin and beta-lactams act synergistically against what?
Enterococci
Spectrum and indications for Gentamicin IV
Spectrum: Gram -ve, Pseudomonas, synergy vs Streptococci and Enterococci with beta-lactam or vancomycin
Indications: Drug resistant UTI, combination therapy for Gram -ve sepsis, synergy for Gram +ve bacteremia and endocarditis
Spectrum and indications for Tobramycin IV
Spectrum: Gram -ve, Pseudomonas (better than gentamicin)
Indications: Drug resistant UTI, combo therapy for serious Pseudomonas infections
Azithromycin is a “BLANK”
Macrolide
Mechanism of action for Macrolides
Inhibit protein synthesis by binding the 23S rRNA in the 50S ribosomal subunit
Macrolides are active against intracellular organisms, true or false?
TRUE
Are Macrolides bacteriostatic or bactericidal?
Bacteriostatic
Does Azithromycin have a long or short half life?
LONG
Spectrum and indications for Azithromycin IV/PO
Spectrum: Mycoplasma, Chlamydophila, Legionella, M. catarrhalis, Chlamydia trachomatis, N. gonorrheae, MAC
Indications: Combo therapy for MAC Tx, MAC prophylaxis in HIV pt’s, 2nd line for STI’s, combo with beta-lactam for CAP
Why is Azithromycin the preferred macrolide over erythromycin and clarithromycin? (5)
- Broader spectrum
- Fewer drug interactions
- Once daily dosing
- Tolerability
- IV option
Clindamycin is a “BLANK”
Lincosamide
What is the mechanism of action of Clindamycin?
Inhibits proteins synthesis by binding to the 50S ribosomal subunit
What is the bioavailability of Clindamycin?
Excellent
Is Clindamycin bacteriostatic or bactericidal?
Bacteriostatic
Clindamycin inhibits toxin production from what?
Group A Streptococcus
Clindamycin is used in combination with what other antibiotic to treat necrotizing faciitis?
Penicillin
Clindamycin is high risk for what?
C. difficile
Spectrum and indications for Clindamycin PO/IV
Spectrum: Streptococci, S. aureus, MRSA (if susceptible), anaerobes
Indications: SSTI, bone/joint, abscesses, alternative for dental infections, polymicrobial infections in combo with Gram -ve agent, combo vs necrotizing faciitis