Figure 2.

Representation of NTHi primary site colonization of the nasopharynx (green) and secondary site infections of the middle ear and lower airways (red). NTHi colonizes the nasopharynx as a commensal organism. In children, NTHi ascends the Eustachian tube to infect the middle ear causing otitis media. During otitis media, the middle ear space, which is normally air filled, contains an inflammatory exudate due to the invading NTHi, resulting in a classic inflamed and bulging tympanic membrane. In adults with COPD, NTHi descends to the lower airways to infect the small airways of the lung. Airflow is restricted in the bronchioles and alveoli of the COPD airways due to chronic inflammation and swelling and collapsed alveolar sacks due to tissue destruction, respectively. NTHi infection of the COPD lower airways contributes to airway inflammation and increased mucous production, further contributing to restricted airflow.