Otomicroscopic findings and systemic interleukin‐6 levels in relation to etiologic agent during experimental acute otitis media

Abstract

The aim of the present study was to explore whether it was possible to differentiate the clinical course and the otomicroscopic appearance of acute otitis media (AOM) caused by common otitis pathogens in an animal model. Systemic interleukin (IL)-6 levels as early markers for bacterial AOM were also studied. Four groups of rats were inoculated with either Streptococcus pneumoniae, Streptococcus pyogenes, non-typeable Haemophilus influenzae or Moraxella catarrhalis. The animals were monitored by otomicroscopy, photos of the tympanic membrane, cultures and IL-6 detection in serum the following 4 days. The gram-positive S. pneumoniae and S. pyogenes induced severe AOM with opaque effusion behind the tympanic membrane, pronounced dilation of the vessels and spontaneous perforations. The gram-negative H. influenzae and M. catarrhalis induced a less severe infection with cloudy, sometimes foamy effusion, and no spontaneous perforations. With the otomicroscopic findings it was possible to distinguish between infections induced by gram-positive bacteria and gram-negative bacteria. Detection of interleukin-6 in serum appeared to be of limited use for all infections except the pneumococcal AOM, but this needs to be further investigated.

Montelukast is as effective as penicillin in treatment of acute otitis media: An experimental rat study

“…As reported previously [7,16], untreated experimental pneumococcal AOM in rats causes changes in the middle ear mucosa that persist for at least 6 months. The histological changes include a thickened mucosa, an increased number of glands, and the occurrence of ciliated cells.…”

Establishment of novel immortalized middle ear cell lines as models for otitis media

“…It has previously been demonstrated that epithelial cells recognize NTHi antigens via TLR2 leading to activation of NF-κB and subsequent upregulation of several key inflammatory mediators including IL-1β, IL-8, and TNF-α. 34,[49][50][51] Consistent with the pattern observed in pediatric MEE primary cultures relative to HMEEC-1, 28 immortalized pediatric lines generally exhibited greater responses in OM-relevant genes to NTHi WCL exposure than did HMEEC-1. Greater responsiveness in pediatric MEE cells relative to HMEEC-1 was observed even for IL6 which did not demonstrate higher baseline expression in pediatric cultures relative to adult HMEEC-1 in the current study or prior study of primary cultures.…”

“…As a critical mediator of the host innate immune system, epithelial cells recognize and respond to invading bacteria through interaction with pathogen‐associated molecular patterns on a variety of bacteria via epithelial expressed TLRs. It has previously been demonstrated that epithelial cells recognize NTHi antigens via TLR2 leading to activation of NF‐κB and subsequent upregulation of several key inflammatory mediators including IL‐1β, IL‐8, and TNF‐α 34,49–51 . Consistent with the pattern observed in pediatric MEE primary cultures relative to HMEEC‐1, 28 immortalized pediatric lines generally exhibited greater responses in OM‐relevant genes to NTHi WCL exposure than did HMEEC‐1.…”

The Role of Inflammatory Mediators in the Pathogenesis of Otitis Media and Sequelae

“…On the contrary, IL-6 was not detected in the guinea pig OM model induced by nonviable H. influenzae (41). Foglé-Ansson et al (83) found that animals inoculated with gram-negative bacteria mediated a faster IL-6 response than animals inoculated with gram-positive bacteria. They also found that it was possible to determine whether an infection was grampositive or negative by analyzing the concentrations of IL-6.…”