Role of adherence of Streptococcus pneumoniae in acute otitis media

The adherence of Streptococcus pneumoniae to human nasopharyngeal epithelial cells was studied as a possible determinant in the development of acute otitis media (AOM). Pneumococcal isolates were obtained from the nasopharynx (NP) and middle ear fluid of infants followed from birth in a prospective study of pneumococcal carriage and infection. The adherence of 33 middle ear fluid isolates from 19 infants with AOM was compared with 143 strains recovered from NP cultures taken from each child both at the time of their acute infections and on other occasions. We studied 171 NP isolates from 29 "carrier" infants, who had no pneumococcal infections, for comparison. Adherence properties were not associated with any particular pneumococcal capsular types, nor were adherent strains more frequent among infants with AOM. There was no evidence to support the hypothesis that pneumococci associated with AOM have a special propensity for adherence. Adherence was a frequent characteristic of pneumococci recovered from the NP, especially in connection with upper respiratory tract infection, and may be required for the establishment of colonization but was not a property that discriminated between carriage strains and those causing AOM.