Acute otitis media in Sweden. Role of Branhamella catarrhalis and the rationale for choice of antimicrobial therapy.

The occurrence of Branhamella catarrhalis in the nasopharynx and middle ear exudate was investigated in 3 studies. Bacteria were isolated from the nasopharynx in 63% of 180 healthy children and B. catarrhalis, the most common bacterium present, was isolated in 36%. In 75 children with primary acute otitis media, bacteria were isolated from the nasopharynx in 98% and from the middle ear exudate in 80%. B. catarrhalis was found in the nasopharynx in 43% and in the middle ear exudate in pure culture in 9%. In those children in whom B. catarrhalis was isolated from the middle ear exudate it was also present in the nasopharynx. In 420 children, 338 with primary acute otitis media and 82 who relapsed or did not respond to previous antibiotic therapy, B. catarrhalis was isolated from the nasopharynx in approximately 50%. About half of the B. catarrhalis strains were beta-lactamase-producing and the majority of these strains were isolated in children under 3 years of age. Of children with primary acute otitis media who had beta-lactamase-producing B. catarrhalis about 50% had not previously received antibiotic treatment. B. catarrhalis is commonly found in the nasopharynx of healthy children as well as in children with acute otitis media. Many of the strains are beta-lactamase-producing though many of the children have not been previously treated with antibiotics. In middle ear exudate, B. catarrhalis is found in about 10% of cases.(ABSTRACT TRUNCATED AT 250 WORDS)