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Morphologic and motility changes of nasal cilia in primary culture caused by Haemophilus influenzae
K Fujihara1, N Yamanaka, J M Bernstein
1Department of Otorhinolaryngology, Wakayama Medical College, Japan.
Abstract:
We focused on the pathogenicity of otitis media with effusion (OME) with respect to the susceptibility of the upper respiratory tract mucosa to Haemophilus influenzae. Human nasal polyps in outgrowth culture were used to study H influenzae disturbance of the ciliary beat frequency (CBF) and the morphology of cilia. The CBF of control primary culture was 11.7 +/- 2.7 Hz. The CBF slowed down significantly, to 8.5 +/- 5.7 Hz, after incubation with the filtrate of 10(8) CFU/mL of H influenzae, and to 4.1 +/- 4.1 Hz with a suspension of 10(8) CFU/mL of H influenzae (p<.05). In the morphologic study, we classified the shapes of the cilia into five types: normal cilia, immotile cilia, swollen cilia, clumped cilia, and exfoliated ciliated cells. The abnormal shapes of cilia increased after incubation with the suspension or the filtrate of H influenzae. By scanning electron microscopy, we saw that aggregated bacteria tended to associate with cilia. Thus, the findings suggest that H influenzae disturbs the ciliary clearance of nasal cells and makes them more susceptible to infections.
Insights
Haemophilus influenzae infection impairs upper respiratory tract cilia function. This study shows the bacteria damages cilia, increasing susceptibility to infections like otitis media with effusion.
Area of Science:
- Microbiology
- Otolaryngology
- Cell Biology
Background:
- Otitis media with effusion (OME) is a common condition affecting the middle ear.
- The role of Haemophilus influenzae in OME pathogenesis and upper respiratory tract susceptibility is not fully understood.
- Ciliary function is crucial for clearing the upper airway mucosa.
Purpose of the Study:
- To investigate the pathogenicity of Haemophilus influenzae concerning upper respiratory tract mucosal susceptibility.
- To examine the effects of H. influenzae on ciliary beat frequency (CBF) and cilia morphology.
- To understand the potential link between H. influenzae and OME.
Main Methods:
- Utilized human nasal polyps in outgrowth culture.
- Measured ciliary beat frequency (CBF) after incubation with H. influenzae filtrate and bacterial suspension.
- Assessed cilia morphology using light microscopy and scanning electron microscopy.
- Quantified H. influenzae load (CFU/mL).
Main Results:
- H. influenzae significantly reduced CBF in cultured nasal polyps.
- Exposure to H. influenzae filtrate and bacterial suspension led to abnormal cilia morphology (swollen, clumped, immotile).
- Scanning electron microscopy revealed bacterial aggregation on cilia, suggesting direct interaction.
- Abnormal cilia shapes increased significantly after H. influenzae exposure.
Conclusions:
- Haemophilus influenzae disrupts the normal ciliary clearance mechanism in the nasal mucosa.
- Impaired ciliary function by H. influenzae may increase susceptibility to respiratory infections, including OME.
- These findings highlight H. influenzae as a significant factor in upper airway mucosal defense breakdown.