Mucosa of infected maxillary sinus, congested, Haemophilus influenzae bacteria, treatments,. The frontal, ethmoidal, sphenoid and maxillary sinuses can be infected by Haemophilus influenzae. Zoom on a section of the lining of the infected and congested maxillary sinus. Right, mucous cells destroyed by bacteria (in green). Purulent secretions are present in the mucus. The submucosal tissue shows dilated blood vessels, leukocytes are trying to destroy the bacteria. Below, zoom on a bacterium seen in section to detail the different sites of action of antibiotics