title: Topical antibiotic treatment reduces tympanostomy tube biofilm formation.
abstract: OBJECTIVE
  Single doses of different ototopical antibiotic preparations (OAPs) have been shown to have an unequal reduction of post tympanostomy tube otorrhea (PTTO). Microbial biofilm formation on the tympanostomy tube (TT) has been implicated as one cause of PTTO. The goal of this study was to determine if TT exposure to a single dose of OAP reduces biofilm formation by Pseudomonas aeruginosa.
  
  
  METHODS
  Prospective and controlled.
  
  
  METHODS
  Fluoroplastic TTs were briefly exposed to plasma, followed by one of three OAPs (ofloxacin, neomycin/polymyxin B/hydrocortisone, or ciprofloxacin/dexamethasone) or saline (20 TT per group). TTs were placed in growth media with P. aeruginosa and incubated for 4 days, during which total bacterial growth was monitored by media turbidity. At 4 days, planktonic organisms were killed and biofilm development was measured with microbial counts.
  
  
  RESULTS
  Bacterial growth was significantly delayed by OAPs, with the least growth seen with ciprofloxacin/dexamethasone followed by ofloxacin and neomycin/polymyxin B/hydrocortisone (P ≤ .0001). At day 4, bacterial growth was less with ciprofloxacin/dexamethasone than ofloxacin and neomycin/polymyxin B/hydrocortisone (P < .05). After 4 days, biofilm counts were lower on OAP-treated than saline-treated TTs (P = .0015) with both ciprofloxacin/dexamethasone and ofloxacin significantly less than saline (P < .05). Biofilm counts were not significantly different between OAPs (P > .05).
  
  
  CONCLUSIONS
  Treatment of TTs with ototopical antibiotic preparations reduces P. aeruginosa growth and biofilm formation in vitro. This may, in part, explain the reduction of PTTO rates observed with single doses of OAPs.
authors: Department of Otolaryngology, University of Florida College of Medicine, Gainesville, Florida 32610-0264, USA.
authors: Robert G
authors: RG
authors: Thomas
authors: Carolyn
authors: C
authors: Ojano-Dirain
authors: Patrick J
authors: PJ
authors: Antonelli
mesh_terms: D000287:Administration, Topical; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D018441:Biofilms / Q000187:drug effects*; D008855:Microscopy, Electron, Scanning; D008876:Middle Ear Ventilation / Q000009:adverse effects / Q000295:instrumentation*; D011446:Prospective Studies; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000502:physiology*
chemical_list: D000900:Anti-Bacterial Agents