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Experimental otitis media induced by coagulase negative staphylococcus and its L-forms
N Göksu1, H Ataoğlu, Y K Kemaloğlu
1Department of Otorhinolaryngology, Gazi University School of Medicine, Ankara, Turkey.
International Journal of Pediatric Otorhinolaryngology
|November 1, 1996
Summary
Bacterial L-forms, particularly coagulase-negative staphylococci (CNS), can cause middle ear infections and may contribute to secretory otitis media (SOM) in animal models. These L-forms induced effusion and tympanic membrane changes, suggesting a role in chronic ear inflammation.
Area of Science:
- Microbiology
- Otolaryngology
- Pathogenesis
Background:
- Previous studies identified bacterial L-forms, predominantly coagulase-negative staphylococci (CNS), in ears with negative conventional cultures.
- Bacterial L-forms are non-culturable variants of bacteria lacking a cell wall.
Purpose of the Study:
- To investigate the pathogenic potential of CNS and its L-forms.
- To determine the role of L-forms in the development of secretory otitis media (SOM).
Main Methods:
- An animal model using guinea pig tympanic bullas was employed.
- Two groups were inoculated: one with CNS and the other with its L-forms.
- Histopathological analysis and observation of effusion and tympanic membrane retraction were conducted over 60 days.
Main Results:
- Both CNS and its L-forms demonstrated infectivity.
- L-form infections were generally milder than those caused by CNS.
- On day 30, 60% of ears inoculated with L-forms showed effusion and/or tympanic membrane retraction, compared to 16.66% with CNS.
- Histopathology revealed hypertrophied pseudostratified epithelium or stratified squamous epithelial metaplasia in L-form inoculated ears.
Conclusions:
- Bacterial L-forms, including CNS L-forms, possess pathogenic capabilities.
- L-forms may play a significant role in the chronic irritation of middle ear mucosa, potentially leading to SOM.