INFECTIOUS DISEASE CASE STUDY 9: Meningitis 

Ricky, a 16-year old white male was brought by ambulance to the emergency room of a community hospital at approximately 10:00 p.m. He was agitated and incoherent. According to his parents, he had complained that morning at breakfast of muscle aches, tiredness, and lack of appetite. When he vomited his breakfast soon after eating, his mother kept him home from school, suspecting influenza, which had been going around the community for a couple of weeks. During the day, he had a severe headache and a midafternoon rise in temperature to 103.5°F. In the evening, Ricky became extremely agitated, began to mutter in an incoherent fashion, and was totally disoriented. His mother consulted the physician and called the ambulatory service. 

Brief physical examination in the emergency room revealed a temperature of 100.8°F and a blood pressure of 150/60 mm Hg. The patient was flailing about in a violent manner. His neck was stiff and a positive Kernig's sign and Brudziniski's neck sign was noted. 

If this infection was of bacterial origin, what three bacteria (genus and species) would most commonly be the cause?