title: Demonstration of biofilm in human bacterial chronic rhinosinusitis.
abstract: BACKGROUND
  Bacterial biofilms may explain why some patients with bacterial chronic rhinosinusitis (CRS) improve while on antibiotics but relapse after completion of the antibiotic. In the human host, biofilms exist as a community of bacteria surrounded by a glycocalyx that is adherent to a foreign body or a mucosal surface with impaired host defense. Biofilms generate planktonic, nonadherent bacterial forms that may metastasize infection and generate systemic illness. These planktonic bacteria are susceptible to antibiotics, unlike the adherent biofilm.
  
  
  METHODS
  We reviewed four cases of CRS using transmission electron microscopy (TEM) to assay for typical colony architecture of biofilms. Bacterial communities surrounded by a glycocalyx of inert cellular membrane materials consistent with a biofilm were shown in two patients.
  
  
  RESULTS
  In the two patients without biofilm, a nonbacterial etiology was discovered (allergic fungal sinusitis) in one and in the other there was scant anaerobic growth on culture and the Gram stain was negative. Culture of the material from the biofilm grew Pseudomonas aeruginosa in both patients. Pseudomonas from the biofilm showed a glycocalyx, not present in Pseudomonas cultured for 72 hours on culture media. Both patients' symptoms with bacterial biofilms were refractory to culture-directed antibiotics, topical steroids, and nasal lavages. Surgery resulted in cure or significant improvement.
  
  
  CONCLUSIONS
  Biofilms are refractory to antibiotics and often only cured by mechanical debridement. We believe this is the first TEM documentation of bacterial biofilms in CRS in humans.
authors.affiliation: Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors.forename: Berrylin J
authors.initials: BJ
authors.lastname: Ferguson
authors.forename: Donna B
authors.initials: DB
authors.lastname: Stolz
mesh_terms: D000328:Adult; D000368:Aged; D001424:Bacterial Infections / Q000382:microbiology* / Q000473:pathology / Q000601:surgery; D018441:Biofilms / Q000254:growth & development*; D001706:Biopsy; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008297:Male; D015523:Maxillary Sinusitis / Q000382:microbiology* / Q000473:pathology / Q000601:surgery; D017348:Microscopy, Electron, Scanning Transmission; D009092:Mucous Membrane / Q000382:microbiology