This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'Which of the following are ineffective against gram negative bacteria? \nSelect and explain. \nA. Cefixime, B. Metronidazole, C. Vancomycine, D. Gentamycine', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Vancomycin is a glycopeptide antibiotic used in the prophylaxis and treatment of infections caused by Gram-positive bacteria. Cefixine is an oral third generation cephalosporin antibiotic. It has good activity for gram-negatives. Metroridozole is highly active against gram-negative anaerobic bacteria, such as B. fragilis, and gram-positive anaerobic bacteria, such as C. difficile. Gentamicin is an aminoglycoside antibiotic, used to treat many types of bacterial infections, paicularly those caused by Gram-negative organisms.', 'role': 'assistant'}]