title: The antibacterial activity of tramadol against bacteria associated with infectious complications after local or regional anesthesia.
abstract: BACKGROUND
  Tramadol is a synthetic analog of codeine with opioid and local anesthetic properties. It is used as a central-acting analgesic, and recently, in subcutaneous or intradermal injections, as a local anesthetic. We investigated in vitro the antibacterial activity of tramadol in the absence of any local anesthetics against Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa pathogens that can cause infectious complications after local or regional anesthesia.
  
  
  METHODS
  Bacterial cultures were grown for 18 h, diluted in sterile physiological saline, and incubated for 6 or 24 h at 37 degrees C with 6.25, 12.5, or 25 mg/mL tramadol. The mixtures were then plated onto blood agar and colony counts were recorded after 24 h incubation at 37 degrees C.
  
  
  RESULTS
  Tramadol had bactericidal activity against E. coli and S. epidermidis compared with controls: at 25 mg/mL for 6 h or at 12.5 mg/mL for 24 h, tramadol decreased by approximately 7 log(10) (P < 0.001) the colony counts of E. coli (100% kill). Similar results were obtained with S. epidermidis, with approximately 6 log(10) reduction (100% kill) when tramadol was used at 25 mg/mL for 24 h (P < 0.001). The antibacterial effect of 25 mg/mL tramadol was lower against S. aureus and P. aeruginosa, reducing the growth of these strains by approximately 3log(10) after 24 h (P < 0.001).
  
  
  CONCLUSIONS
  Tramadol has dose- and time-dependent bactericidal activity against E. coli and S. epidermidis, as well as antibacterial activity against S. aureus and P. aeruginosa. The antibacterial properties of tramadol may be useful for reducing the risk of bacterial infection after local or regional anesthesia.
authors.affiliation: Equipe de Microbiologie, UPRES-EA 1254, Université de Rennes I, Rennes Cedex, France.
authors.forename: Zohreh
authors.initials: Z
authors.lastname: Tamanai-Shacoori
authors.forename: Valliollah
authors.initials: V
authors.lastname: Shacoori
authors.forename: Anne
authors.initials: A
authors.lastname: Jolivet-Gougeon
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Vo Van
authors.forename: Martine
authors.initials: M
authors.lastname: Repère
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Donnio
authors.forename: Martine
authors.initials: M
authors.lastname: Bonnaure-Mallet
mesh_terms: D000765:Anesthesia, Conduction / Q000009:adverse effects*; D000772:Anesthesia, Local / Q000009:adverse effects*; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001424:Bacterial Infections / Q000188:drug therapy* / Q000209:etiology / Q000382:microbiology; D004305:Dose-Response Relationship, Drug; D008826:Microbial Sensitivity Tests / Q000379:methods; D011183:Postoperative Complications / Q000188:drug therapy* / Q000209:etiology / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000254:growth & development; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development; D013212:Staphylococcus epidermidis / Q000187:drug effects / Q000254:growth & development; D013997:Time Factors; D014147:Tramadol / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D014147:Tramadol