Bacterial Sinusitis

Though bacteria are the most common infectious agents in sinusitis, the role of bacteria or other infectious agents is complicated in chronic sinusitis. They may play a direct or an indirect role.

The bacteria most commonly implicated in sinusitis are the following:

Streptococcus pneumoniae (also called pneumococcal pneumonia or pneumococci). This bacterium is found in between 20% and 43% of adults and children with sinusitis.

H. influenzae (a common bacteria associated with many upper respiratory infections). This bacterium colonizes nearly half of all children by age two, and it causes about 25% of sinusitis cases in this group. Studies have reported the presence of this bacterium in 22% to 35% of adult sinusitis patients.

Moraxella catarrhalis . Over three-quarters of all children harbor this bacterium and it causes about 25% of sinusitis cases.

Staphylococcus aureus. About 20% of chronic sinusitis cases are caused by Staphylococcus aureus (commonly called Staph infection). This bacteria may be present but is not usually the infecting agent in acute sinusitis.

Along with other bacteria, certain anaerobic bacteria, particularly the species Peptostreptococcus, Fusobacterium, and Prevotella, are found in 88% of cultures in chronic sinusitis cases. (Anaerobic bacteria exist without air.)

Bacterial sinusitis is generally considered harmless, although it causes great discomfort and is often very painful. When the episode becomes severe, antibiotics generally eliminate further problems.