Differences in nasopharyngeal bacterial flora in children with nonsevere recurrent acute otitis media and chronic otitis media with effusion: implications for management.

Background: The interactions between nasopharyngeal flora and the individual entities covered by the broad term otitis media have not been completely elucidated. We investigated in infants and children ages 6 months to 7 years with nonsevere recurrent acute otitis media (rAOM) or with chronic otitis media with effusion (cOME): (1) the nasopharyngeal carriage rate and bacterial density of respiratory pathogens and alpha-hemolytic streptococci in comparison with healthy children; (2) the resistance pattern of respiratory pathogens; and (3) the relationship between the type of nasopharyngeal colonization and long term outcome.

Methods: Nasopharyngeal cultures were obtained from 85 children with rAOM,113 children with cOME and 55 controls. A semiquantitative analysis was used in the reading of cultures. A 12-week follow-up without treatment was planned.

Results: The carrier rate of respiratory pathogens was significantly greater in cOME (70%) than in rAOM (45%) (P = 0.0006) or controls (31%) (P < 0.0001). Similarly colonization density was significantly greater in cOME than in rAOM. The carriage rate and the colonization density of alpha-hemolytic streptococci were significantly lower in rAOM than in cOME or controls. The incidence of resistant (R) strains was greater in rAOM (Streptococcus pneumoniae penicillin-R, 24%; macrolide-R, 64%; Haemophilus influenzae amoxicillin-R, 24%) compared with cOME (S. pneumoniae penicillin-R,18%; macrolide-R, 44%; H. influenzae amoxicillin-R, 5%) or controls (S. pneumoniae penicillin-R, 8%; macrolide-R, 23%; H. influenzae amoxicillin-R, 10%). During the follow-up period persistence of OME and occurrence of AOM were greater among carriers of respiratory pathogens at baseline.

Conclusions: There are substantial differences in nasopharyngeal flora between children with nonsevere rAOM and children with cOME. The results of nasopharyngeal cultures should be taken into account to avoid treatment with drugs that are ineffective and likely to select resistant organisms.