A 2 year old child is brought to the emergency department with a history of fever and vomiting. On examination he has neck rigidity. CSF examination shows polymorphs more than 2000/microL, protein 100 mg/dL, and glucose 10 mg/dL. Gram stain shows Gram negative coccobacilli. Culture shows growth of bacteria only on chocolate agar and not on blood agar. The causative agent is