title: Assessing the antibiotic potential of essential oils against Haemophilus ducreyi.
abstract: BACKGROUND
  Haemophilus ducreyi is the bacterium responsible for the genital ulcer disease chancroid, a cofactor for the transmission of HIV, and it is resistant to many antibiotics. With the goal of exploring possible alternative treatments, we tested essential oils (EOs) for their efficacy as antimicrobial agents against H. ducreyi.
  
  
  METHODS
  We determine the minimum inhibitory concentration (MIC) of Cinnamomum verum (cinnamon), Eugenia caryophyllus (clove) and Thymus satureioides (thyme) oil against 9 strains of H. ducreyi using the agar dilution method. We also determined the minimum lethal concentration for each oil by subculturing from the MIC plates onto fresh agar without essential oil. For both tests, we used a 2-way ANOVA to evaluate whether antibiotic-resistant strains had a different sensitivity to the oils relative to non-resistant strains.
  
  
  RESULTS
  All 3 oils demonstrated excellent activity against H. ducreyi, with MICs of 0.05 to 0.52 mg/mL and MLCs of 0.1-0.5 mg/mL. Antibiotic-resistant strains of H. ducreyi were equally susceptible to these 3 essential oils relative to non-resistant strains (p=0.409).
  
  
  CONCLUSIONS
  E. caryophyllus, C. verum and T. satureioides oils are promising alternatives to antibiotic treatment for chancroid.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Lindeman
authors.forename: Molly
authors.initials: M
authors.lastname: Waggoner
authors.forename: Audra
authors.initials: A
authors.lastname: Batdorff
authors.affiliation: Allegheny College Department of Biology, 520 N, Main St,, Meadville, PA 16335, USA. thumphre@allegheny.edu.
authors.forename: Tricia L
authors.initials: TL
authors.lastname: Humphreys
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000494:pharmacology; D002602:Chancroid / Q000188:drug therapy; D002935:Cinnamomum zeylanicum / Q000737:chemistry*; D006191:Haemophilus ducreyi / Q000187:drug effects*; D006801:Humans; D008826:Microbial Sensitivity Tests; D009822:Oils, Volatile / Q000494:pharmacology* / Q000627:therapeutic use; D008517:Phytotherapy; D027842:Syzygium / Q000737:chemistry*; D046930:Thymus Plant / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D009822:Oils, Volatile