<s>[INST] context: GLYCOPEPTIDE ANTIBIOTICS Vancomycin It is a glycopeptide antibiotic discovered in 1956 as a penicillin substitute which has assumed special significance due to efficacy against MRSA Strep. viridans, Enterococcus and Cl. difficile. It is bactericidal to gram-positive cocci, Neisseria, Clostridia and diphtheroids. However, in hospitals where it has been extensively used for surgical prophylaxis, etc., vancomycin-resistant Staph. aureus (VRSA) and vancomycin-resistant Enterococcus (VRE) have emerged. These nosocomial bacteria are resistant to methicillin and most other antibiotics as well. Teicoplanin It is a newer glycopeptide antibiotic which in fact is a mixture of 6 similar compounds. It is active against gram-positive bacteria only; mechanism of action and spectrum of activity is similar to vancomycin. Notable features are: * It is more active than vancomycin against enterococci, and equally active against MRSA. * Some VRE but not VRSA are susceptible to teicoplanin. ESSENTIALS OF MEDICAL PHARMACOLOGY K.D.TRIPATHI SIXTH EDITION PAGE NO:732,733 [/INST] question: Drug of choice for treatment of infection caused by methicillin resistant staphylococcus aureus is: | options: A: Macrolides B: Third generation cephalosporins C: Carbapenems D: Glycopeptides | answer: D </s>