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Alloiococcus otitidis--otitis media pathogen or normal bacterial flora?

Krister Tano¹, Robert von Essen, P O Eriksson

¹Department of Clinical Science, Otorhinolaryngology, Sunderby Hospital, Luleå, Sweden. krister.tano@nll.se

APMIS : Acta Pathologica, Microbiologica, Et Immunologica Scandinavica

|November 26, 2008

Summary

Alloiococcus otitidis was found in healthy ear canals, suggesting it is normal flora, not a pathogen. A rat model showed mild middle ear reactions, questioning its role in otitis media.

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Conjunctival Commensal Isolation and Identification in Mice

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Published on: May 1, 2021

Area of Science:

Microbiology
Otolaryngology
Infectious Diseases

Background:

Alloiococcus otitidis is a potential pathogen in otitis media, frequently found in middle ear effusions.
Its role as a pathogen remains unclear, necessitating further investigation.

Purpose of the Study:

To determine the presence of Alloiococcus otitidis in the nasopharynx and outer ear canals.
To develop a reliable culture method for isolating A. otitidis.
To assess the pathogenicity of A. otitidis in a rat model of acute otitis media.

Main Methods:

Investigated nasopharyngeal and outer ear canal samples from children and healthy individuals using PCR and conventional culture.
Utilized a rat model to evaluate the clinical outcome of A. otitidis middle ear infections.
Developed a culture method using blood agar plates with 6% saline and specific antisera.

Main Results:

A. otitidis was detected by PCR in 7% of children's nasopharynxes and 29% of healthy outer ear canals.
Conventional culture successfully isolated A. otitidis from healthy ear canals but not from nasopharyngeal samples.
The rat model demonstrated mild middle ear responses, failing to induce purulent acute otitis media.

Conclusions:

Alloiococcus otitidis appears to be a commensal bacterium in the healthy outer ear canal flora.
The study questions the pathogenicity of A. otitidis in causing acute otitis media.
A modified culture method using 6% saline blood agar is effective for isolating A. otitidis from the outer ear canal.