Association of nasopharyngeal bacterial colonization during upper respiratory tract infection and the development of acute otitis media.

Acute otitis media occurs mostly after upper respiratory tract infection; the causative bacteria are those colonized in the nasopharynx. We studied 709 episodes of upper respiratory tract infection and found that children with no bacteria in the nasopharynx were at low risk for acute otitis media, whereas children with 3 pathogenic bacteria were at the greatest risk.