Biotypes of serologically nontypable Haemophilus influenzae isolated from the middle ears and nasopharynges of patients with otitis media with effusion

Abstract
A biotype analysis was performed on serologically nontypable H. influenzae isolates from the middle ear effusions and nasopharynges of 33 children with chronic otitis media with effusion (serous otitis media). Over 50% of the H. influenzae isolates from the middle ears belonged to biotype II. The incidence of .beta.-lactamase production was 17%. Evidently, future clinical or experimental investigations of chronic otitis media with effusion induced by serologically nontypable H. influenzae should focus on this clinically important biotype.