system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 5-year-old boy presents to the clinic for evaluation of symptoms of left ear pain and associated fever. On physical examination, the left eardrum is inflamed with a small perforation in it and pus is seen in the external canal. A swab of the fluid grows S pneumoniae. Which of the following is the most likely mechanism for S pneumoniae to cause otitis media?
assistant
The correct answer is  Infections of the middle ear, trachea, sinuses, bronchi, and lungs are caused by direct spread from nasopharyngeal colonization. Disease of the CNS, heart valves, bones, joints, and peritoneal are usually caused by hematogenous dissemination.