A 6-year-old boy is brought to the pediatrician for evaluation of left ear pain. The patient's mother states, “He has been tugging on his left ear for the past three days; he just cannot seem to get any relief.” The patient has been taking tylenol at home for symptomatic relief. Temperature is 38.0°C (100.4°F), pulse
is 99/min, respirations are 16/min, and blood pressure
is 100/65 mmHg. Physical examination is notable for the following finding:
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Which of the following pathogens is the most likely cause of this patient’s clinical presentation?