<s>[INST] context: 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. Uses: Given orally (125-500 mg 6 hourly), it is the second choice drug to metronidazole for antibiotic associated pseudomembranous enterocolitis caused by C. difficile. Systemic use (500 mg 6 hourly or 1 g 12 hourly infused i.v. over 1 hr) is restricted to serious MRSA infections for which it is the most effective drug. and as a penicillin substitute (in allergic patients 1 for enterococcal endocarditis along with gentamicin. For empirical therapy of bacterial meningitis, i.v. vancomycin is usually combined with i.v. ceftriaxone/ cefotaxime. It is also used in dialysis patients and those undergoing cancer chemotherapy. Penicillin-resistant pneumococca: infections and infection caused by diphtheroids respond very well to vancomycin. It is the preferred surgical prophylactic in MRSA prevalent areas and in penicillin allergi.: patients. ESSENTIALS OF MEDICAL PHARMACOLOGY K.D.TRIPATHI SIXTH EDITION PAGE NO:732 [/INST] question: Which of the following is not an anti-pseudomonal agent? | options: A: Vancomycin B: Ticarcillin C: Ceftazidime D: Tobramycin | answer: A </s>