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Purified streptococcal cell wall (PG-APS) causes experimental otitis media
1Department of Microbiology and Immunology, School of Medicine, East Carolina University, Greenville, NC 27858, USA.
Auris, Nasus, Larynx
|March 26, 1998
Summary
Group A Streptococcus pyogenes peptidoglycan-polysaccharide (PG-APS) caused mild middle ear inflammation in gerbils, with most recovering within 14 days. Subsequent PG-APS challenge did not worsen inflammation.
Area of Science:
- Microbiology
- Immunology
- Otolaryngology
Background:
- Group A Streptococcus pyogenes is a significant human pathogen.
- Understanding the host response to bacterial components is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the inflammatory response in the middle ear cavity (MEC) to purified peptidoglycan-polysaccharide (PG-APS) from Group A Streptococcus pyogenes.
- To assess the resolution of inflammation and potential for exacerbation upon re-challenge.
Main Methods:
- Sterile, pyrogen-free PG-APS was percutaneously injected into the MEC of gerbils.
- Animals were monitored otoscopically and histologically at various time points (1-14 days).
- A subset of animals received an intraperitoneal PG-APS challenge 14 days post-MEC injection.
Main Results:
- PG-APS induced mild acute inflammation in the early stages (first 3 days).
- Mild to moderate inflammation with acute and chronic features was observed from days 5-9, with plasma cell and macrophage infiltration.
- Most gerbils showed recovery with minor sequelae by day 14.
- Intraperitoneal PG-APS challenge did not exacerbate middle ear inflammation.
Conclusions:
- PG-APS from Group A Streptococcus pyogenes elicits a transient inflammatory response in the gerbil middle ear.
- The middle ear appears to resolve PG-APS-induced inflammation effectively within 14 days.
- The study suggests a limited capacity for immune priming or potentiation of inflammation by PG-APS in this model.