title: Non-preserved 1% lidocaine solution has less antibacterial properties than currently available anaesthetic eye-drops.
abstract: OBJECTIVE
  Some anaesthetics inhibit bacterial growth, and thus may lead to low rates of positive cultures from bacterial keratitis. Antibacterial properties of lidocaine were compared with those of oxybuprocaine or tetracaine, either in current commercial eye lotions or in extemporaneous solutions.
  
  
  METHODS
  Forty-eight bacterial strains were used to determine the minimum inhibitory and bactericidal concentrations of four commercial eye lotions containing oxybuprocaine or tetracaine, of a non-ophthalmic 1% lidocaine commercial solution and of extemporaneously prepared solutions of oxybuprocaine, tetracaine, lidocaine and benzalkonium.
  
  
  RESULTS
  Most strains had their growth inhibited by 0.2% oxybuprocaine or 0.4% tetracaine, which corresponds to a 1/2 dilution of the commercial eye-drops. Bacterial growth was still observed with a 1% lidocaine solution.
  
  
  CONCLUSIONS
  Currently available anaesthetic eye-drops that are used before corneal specimen collection may lead to false-negative bacterial cultures. Conversely, a non-preserved 1% lidocaine solution might be more appropriate in corneal specimen collection.
authors.affiliation: Department of Ophthalmology, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, Faculté de Médecine Paris-Sud, Paris, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Labetoulle
authors.forename: Eric
authors.initials: E
authors.lastname: Frau
authors.forename: Hervé
authors.initials: H
authors.lastname: Offret
authors.forename: Patrice
authors.initials: P
authors.lastname: Nordmann
authors.forename: Thierry
authors.initials: T
authors.lastname: Naas
mesh_terms: D000779:Anesthetics, Local / Q000494:pharmacology*; D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D001548:Benzalkonium Compounds / Q000494:pharmacology; D008012:Lidocaine / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009883:Ophthalmic Solutions; D011310:Preservatives, Pharmaceutical / Q000494:pharmacology; D011343:Procaine / Q000031:analogs & derivatives* / Q000494:pharmacology; D013748:Tetracaine / Q000494:pharmacology
chemical_list: D000779:Anesthetics, Local; D000891:Anti-Infective Agents, Local; D001548:Benzalkonium Compounds; D009883:Ophthalmic Solutions; D011310:Preservatives, Pharmaceutical; D013748:Tetracaine; D011343:Procaine; D008012:Lidocaine; C005298:benoxinate