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': 'Moraxella catarrhalis is resistant to which antibiotic? \nSelect and explain. \nA. Amoxicillin, B. Clarithromycin, C. Azithromycin, D. Amoxicillin and clavulanic acid combination', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Amoxicillin Treatment of M. caterrahlis infection: M. catarrhalisrapidly acquired -lactamases during the 1970s and 1980s; antimicrobial susceptibility patterns have remained relatively stable since that time, with >90% of strains now producing -lactamase and thus resistant to amoxicillin. Most strains of M. catarrhalisare susceptible to amoxicillin and clavulanic acid combination, extended-spectrum cephalosporins, newer macrolides (azithromycin, clarithromycin), trimethoprim- sulfamethoxazole, and fluoroquinolones.", 'role': 'assistant'}]