Haemophilus influenzae infection
Haemophilus influenzae is a common cause of epiglottiditis, laryngotracheobronchitis, pneumonia, bronchiolitis, otitis media, and meningitis. Less commonly, it causes bacterial endocarditis, conjunctivitis, facial cellulitis, septic arthritis, and osteomyelitis.
H. influenzae pneumonia is an increasingly common nosocomial infection. It’s the second-leading cause of bacterial pneumonia deaths in children. Breast-feeding during the first 6 months provides passive protection of some infants. It infects about one-half of all children before age 1 and virtually all children by age 3, although a new vaccine given at ages 2, 4, and 6 months has reduced this number.
Causes
A small, gram-negative, pleomorphic aerobic bacillus, H. influenzae causes diseases in many organ systems but most frequently attacks the respiratory system. In exudates, this organism predominantly resembles a coccobacillus. It’s transmitted by airborne droplets or direct contact with secretions or fomites.
Signs and symptoms
H. influenzae provokes a characteristic tissue response—acute suppurative inflammation.
