Haemophilus influenzae biofilm formation in chronic otitis media with effusion

Abstract

Otitis media with effusion (OME) is a highly prevalent disease in children, but the exact pathogenesis and role of bacteria are still not well understood. This study aimed to investigate the presence of otopathogenic bacteria in the middle ear effusion (MEE) and adenoid of children with chronic OME (COME), and to investigate in vivo whether these bacteria, especially Haemophilus influenzae, are organized as a biofilm in the middle ear fluid. MEE and adenoid samples were collected from 21 patients with COME. Extensive bacterial culturing and genotyping was performed on all middle ear and adenoid samples. Fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) was used to visualize possible biofilm structures for a selection of middle ear effusion samples. 34 MEE samples were collected from 21 patients of which 64.7 % were culture positive for bacteria and 47.0 % were culture positive for Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus and/or Streptococcus pneumoniae. All 21 adenoid samples were culture positive for one or more of these four otopathogens. H. influenzae (35.3 %) and S. pneumoniae (76.2 %) were the most frequently cultured bacteria in the MEE and adenoid samples, respectively. The same bacterial species was found in MEE and adenoid for 84.6 % of the patients and in 81.2 % of the cases where the same species was found in more than one site it involved the same bacterial genotype. FISH and CLSM demonstrated the presence of H. influenzae specific biofilm structures in five of the eight culture positive MEEs that were tested, but in none of the two culture negative MEEs. The findings in this study indicate that the adenoid acts as a reservoir for bacteria in MEE and confirms that biofilms, in at least half of the cases consisting of H. influenzae, are indeed present in the MEE of children with COME. Biofilms may thus play a crucial role in the pathogenesis of COME, which is important in the understanding of this disease and the development of potential future treatment options.

Otitis media

“…Bacterial biofilms (that is, colonization of bacteria embedded in the extracellular matrix and adherent to a surface), which are known to protect bacteria against antibiotic treatment 56,57 and the host's immune response, have been demonstrated in the middle ears of patients with CSOM 58,59 , persistent OME 58,60 and those with OM who have failed antibiotic treatment 60 . Biofilms have been reported to occur in MEE 60 , attached to the middle ear mucosa 61 .…”

Identification of essential biofilm proteins in middle ear fluids of otitis media with effusion patients

“…Hall‐Stoodley et al demonstrated biofilms in biopsy specimens from the middle ears of children undergoing tympanostomy tube placement for chronic OME and/or recurrent otitis media but not in those of control children undergoing cochlear implantation . Later, Van Hoecke et al detected the presence of Haemophilus influenzae‐ specific biofilm structures in culture‐positive but not culture‐negative middle ear effusions using fluorescence in situ hybridization . Ours is the first investigation to identify and quantitate two essential biofilm structural components, IHF and HU, within effusions recovered from children with chronic OME.…”

“…12 Later, Van Hoecke et al detected the presence of Haemophilus influenzae-specific biofilm structures in culture-positive but not culture-negative middle ear effusions using fluorescence in situ hybridization. 32 Ours is the first investigation to identify and quantitate two essential biofilm structural components, IHF and HU, within effusions recovered from children with chronic OME. Previous work has already shown that biofilms formed by nontypeable Haemophilus influenzae contain eDNA organized into a mesh-like lattice, with bacterial DNABII DNA-binding proteins located at the vertices of crossed strands of eDNA.…”

Diagnóstico y tratamiento de la otitis media secretora infantil: recomendaciones CODEPEH 2016

“…Esta área de investigación tiene su base en la existencia de biofilms bacterianos en el oído medio y, sobre todo, en las adenoides que podrían tener relación con la OMS y la OMA, actuando como reservorio de patógenos, lo que podría abrir nuevas opciones terapéuticas (Tawfik et al, 2016;Van Hoecke et al, 2016;Davcheva-Chakar et al, 2015: 71-76).…”