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The role of bacterial adherence in otitis media with effusion
K Shimamura1, H Shigemi, Y Kurono
1Department of Otolaryngology, Medical College of Oita, Japan.
Insights
Bacterial adherence to the nasopharynx is higher in children, especially those with otitis media with effusion. Secretory IgA may reduce this adherence, suggesting a role in preventing middle ear infections.
Area of Science:
- Microbiology
- Immunology
- Otolaryngology
Background:
- Nontypable Haemophilus influenzae and Streptococcus pneumoniae are common causes of childhood respiratory infections.
- Otitis media with effusion (OME) is a frequent complication in children, often linked to bacterial colonization of the nasopharynx.
Purpose of the Study:
- To investigate the in vitro adherence of H. influenzae and S. pneumoniae to nasopharyngeal epithelial cells.
- To explore age-related differences and the influence of OME on bacterial adherence.
- To examine the role of secretory IgA in nasopharyngeal secretions in modulating bacterial adherence.
Main Methods:
- In vitro adherence assays using nasopharyngeal epithelial cells from children and adults.
- Comparison of adherence in children with and without OME.
- Measurement of secretory IgA antibody activity in nasopharyngeal secretions and correlation with bacterial adherence.
Main Results:
- Both H. influenzae and S. pneumoniae exhibited greater adherence to epithelial cells from children than adults.
- Bacterial adherence was significantly higher in children with OME compared to healthy children.
- Presence of secretory IgA antibody activity against the bacteria correlated with significantly reduced bacterial adherence.
Conclusions:
- Bacterial adherence to the nasopharynx is a key factor in the pathogenesis of OME in children.
- Secretory IgA in nasopharyngeal secretions plays a protective role by decreasing bacterial adherence, potentially preventing OME.
Abstract:
Adherence of nontypable Haemophilus influenzae and Streptococcus pneumoniae to nasopharyngeal epithelial cells was investigated in vitro. Both strains had higher affinity to the epithelial cells of children than to those of adults. In children, the adherence was significantly greater in patients with otitis media with effusion than in normal subjects. Secretory IgA in nasopharyngeal secretions was found to have antibody activity against the bacteria. Adherence of both bacteria was significantly smaller in the group having secretory IgA antibody activity than in the group having no activity. These results suggest that bacterial adherence to the nasopharynx may play an important role in the pathogenesis of otitis media with effusion in children, and that secretory IgA in nasopharyngeal secretions may be related to the decrease of adherence.