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:
Image reproduced from Wikimedia Commons
Which of the following pathogens is the most likely cause of this patient’s clinical presentation?