title: Bacterial-induced epithelial damage promotes fungal biofilm formation in a sheep model of sinusitis.
abstract: BACKGROUND
  Fungal biofilms have been discovered in chronic rhinosinusitis (CRS) patients, but factors contributing to their establishment are obscure. A recent animal study showed bacterial co-inoculation was required. We examine the role of 4 bacterial species and a cilia toxin on fungal biofilm formation in a sheep sinusitis model. The importance of epithelial integrity on fungal biofilm formation is also examined.
  
  
  METHODS
  Forty-eight frontal sinuses were inoculated with Aspergillus fumigatus alone, with 1 of 4 bacteria, or a cilia toxin. Bacterial and fungal biofilm was determined using confocal scanning laser microscopy. Inflammation and cilia integrity were assessed using light microscopy and transmission electron microscopy, respectively.
  
  
  RESULTS
  No fungal biofilm formed when inoculated alone. Florid fungal biofilm developed in more than 75% of sinuses associated with bacterial biofilm of all species, except Haemophilus influenzae, which failed to establish bacterial biofilm. Fungal biofilm also established in association with cilia toxin. Significant cilial damage was incited by all bacterial biofilms and cilia toxin, and was associated with fungal proliferation. Fungal biofilm formation did not significantly increase mucosal inflammation or epithelial damage over that caused by the bacteria or cilia toxin alone.
  
  
  CONCLUSIONS
  Bacterial biofilms cause sinonasal mucosal inflammation and epithelial injury, which provides conditions appropriate for fungal biofilm proliferation. The role of cilia in sinonasal mucosal defense against fungal organisms has been demonstrated. Without such an insult, fungal biofilms fail to proliferate in occluded sinuses. Improving cilial recovery postoperatively and treating bacterial biofilms may be key factors in reducing recalcitrance in allergic fungal rhinosinusitis patients.
authors: Department of Surgery-Otorhinolaryngology, Head and Neck Surgery, University of Adelaide, Adelaide, Australia.
authors: Sam
authors: S
authors: Boase
authors: Joshua
authors: J
authors: Jervis-Bardy
authors: Edward
authors: E
authors: Cleland
authors: Harshita
authors: H
authors: Pant
authors: Lorwai
authors: L
authors: Tan
authors: Peter-John
authors: PJ
authors: Wormald
mesh_terms: D000818:Animals; D001228:Aspergillosis / Q000209:etiology / Q000276:immunology*; D001232:Aspergillus fumigatus / Q000502:physiology*; D001424:Bacterial Infections / Q000150:complications / Q000276:immunology*; D001427:Bacterial Toxins / Q000276:immunology; D018441:Biofilms / Q000254:growth & development*; D002908:Chronic Disease; D002923:Cilia / Q000648:ultrastructure; D004195:Disease Models, Animal; D006801:Humans; D009297:Nasal Mucosa / Q000276:immunology* / Q000382:microbiology; D020545:Respiratory Mucosa / Q000276:immunology* / Q000382:microbiology / Q000648:ultrastructure; D012220:Rhinitis / Q000276:immunology*; D012756:Sheep; D012852:Sinusitis / Q000276:immunology*
chemical_list: D001427:Bacterial Toxins