Haemophilus influenzae (Pfeiffer's bacillus). In its unencapsulated form it is responsible for local infections: otitis, sinusitis, pharyngitis, conjunctivitis. In its encapsulated form it can be responsible for: ear infections, meningitis, epiglottitis, occurring almost exclusively in children up to the age of six, as well as septicemia and pneumonia. Image colorization of microscopy; magnification X 1000.