Therapy for Staph and Strep II Flashcards
What type of compound is vancomycin?
Glycopeptide
Vancomycin mechanism of action?
Prevents cell wall synthesis, binds to d-ala-d-ala, prevents elongation and cross linking.
Resistance to vancomycin?
D-Ala-D-Ala turned into D-Ala-D-Lactate, Vanco can’t bind. Also, thickened cell wall.
What types of organisms does vancomycin affect?
Only gram positive organisms
Is vancomycin bactericidal or bacteriostatic?
Slowly bactericidal, but bacteriostatic against enterococci
What is vancomycin the drug of choice to treat?
MRSA and penicillin-resistent pneumococcus
Why is the oral formulation used to treat C. diff?
Because it isn’t absorbed, so it doesn’t work systemically, only in gut lumen.
Toxicity of vancomycin?
Nephrotoxicity, hypersensitivity (red man syndrome).
Red Man syndrome
Histamine response to rapid vanco infusion. Huge widespread rash.
What type of compound is daptomycin?
A cyclic lipopeptide
What type of organisms does daptomycin treat?
Gram positive organisms (MRSA, MSSA, Enterococci, VRE). NO gram negative activity
VRE
Vancomycin resistent enterococci.
Does daptomycin have gram negative activity?
No!
How does daptomycin work?
Binds to the cytoplasmic membrane using Ca and causes rapid depolarization, leading to intracellular ion release. Rapid bactericidal action, concentration dependent mechanism.
What type of infections is daptomycin used for?
Skin and soft tissue infections. MSSA, MRSA, bloodstream infections. VRE.
What isn’t daptomycin used for pneumonia?
It is inactivated by pulmonary surfactant.
Adverse effects of daptomycin
Musculoskeletal pains, weakness, rhabdomyolysis
Who is at increased risk for rhabdomyolysis when taking daptomycin? What to do to monitor?
Those on statins! Check CPK (creatine phosphokinase) levels and monitor muscle strength.
Inhibitors of protein synthesis in gram positive cocci
Linezolid, doxycycline, clindamycin. These drugs are bacteriostatic.