title: Tea tree oil: in vitro efficacy in otitis externa.
abstract: OBJECTIVE
  The purpose of this study was to determine the susceptibility of organisms causing otitis externa (OE) to the essential oil of Melaleuca alternifolia, or tea tree oil (TTO).
  
  
  METHODS
  Fifty-seven swabs were taken from the ears of 52 patients with OE for culture and sensitivity. A broth microdilution method was used to determine the minimum inhibitory concentration (MIC) of TTO for each organism.
  
  
  RESULTS
  In 51 percent of the swabs taken, pathogenic organisms were cultured. Of these cultures 71 percent, both bacteria and yeast, were susceptible to TTO 2 percent or less. The only organism showing resistance to TTO was Pseudomonas aeruginosa; however 25 percent of these bacteria were sensitive.
  
  
  CONCLUSIONS
  Tea tree oil may have a role to play in the treatment of OE. However, more work needs to be done to enhance the anti-pseudomonal effect and to assess ototoxicity.
authors.affiliation: Department of Otolaryngology, Craigavon Area Hospital, Northern Ireland, UK. t.farnan@ntlworld.com
authors.forename: T B
authors.initials: TB
authors.lastname: Farnan
authors.forename: J
authors.initials: J
authors.lastname: McCallum
authors.forename: A
authors.initials: A
authors.lastname: Awa
authors.forename: A D
authors.initials: AD
authors.lastname: Khan
authors.forename: S J
authors.initials: SJ
authors.lastname: Hall
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010032:Otitis Externa / Q000188:drug therapy / Q000382:microbiology*; D008517:Phytotherapy; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D020947:Tea Tree Oil / Q000494:pharmacology*
chemical_list: D000891:Anti-Infective Agents, Local; D020947:Tea Tree Oil