Which bacterium is a common cause of otitis media?

Streptococcus pneumoniae is a leading cause of otitis media, which is an infection or inflammation of the middle ear. This bacterium is commonly implicated in pediatric populations, particularly in children under the age of five, due to their anatomical and immunological characteristics.

S. pneumoniae possesses virulence factors such as its capsule, which enables it to evade phagocytosis by immune cells, ultimately contributing to its ability to cause infections like otitis media. The presence of this bacterium in the nasopharynx can lead to an upward spread into the middle ear through the Eustachian tube, especially in cases where there are concurrent upper respiratory tract infections.

In contrast, while Escherichia coli is more commonly associated with gastrointestinal infections and urinary tract infections, and Staphylococcus aureus is often linked to skin and soft tissue infections, both are not typical causes of otitis media. Neisseria meningitidis primarily causes meningitis and sepsis, and is not associated with middle ear infections. These distinctions underline the significance of S. pneumoniae in pediatric ear infections.