EVALUATION OF THE ANTIMICROBIAL EFFECTS OF TOPICAL ANESTHETIC AGENTS Selim Doganay, MD¹; Gozde Orman, MD¹; Cem Cankaya, MD¹; Selami Gunal, MD²; Baris Otlu, MD² Inonu University School of Medicine, Malatya-Turkey ¹ Department of Ophthalmology, ² Department of Microbiology Authors have no financial or proprietary interest in any instrument or products used in this study

Purpose  To investigate the antimicrobial effects of topical anesthetic agents. EVALUATION OF THE ANTIMICROBIAL EFFECTS OF TOPICAL ANESTHETIC AGENTS

Introduction  The using of topical anesthetics shown in various studies to have anti-bacterial activities, before taking conjunctival and/or corneal samples may lead to false culture results. 1-8 EVALUATION OF THE ANTIMICROBIAL EFFECTS OF TOPICAL ANESTHETIC AGENTS

Materials and methods  Test drugs (oxybuprocaine 0.4%, Proparacaine hydrochloride 0.5%, Lidocaine 10%) were tested for Staphylococcus aureus (S. aureus) ATCC 29213, Streptococcus pneumoniae (S. pneumoniae) ATCC 27336, Pseudomonas aeruginosa (P. aeruginosa) ATCC 27853, standard strains of Escherichia coli (E. coli) ATCC 25922, and Candida albicans (C. albicans) using modified microplate alamar blue method (MABA) in different concentrations according to Clinical and Laboratory Standards Institute (CLSI) criteria. EVALUATION OF THE ANTIMICROBIAL EFFECTS OF TOPICAL ANESTHETIC AGENTS

Results  S. Pneumoniae proliferated in none of the dilutions of three topical anesthetics. S. aureus proliferated in all dilutions of oxybuprocaine and lidocaine, and in no dilutions of proparacaine hydrochloride.  P. Aeruginosa proliferated in 0.2% dilution of oxybuprocaine and 2.5% and 5% dilutions of lidocaine and in all dilutions of proparacaine hydrochloride. EVALUATION OF THE ANTIMICROBIAL EFFECTS OF TOPICAL ANESTHETIC AGENTS

Results  C. albicans proliferated in 0.05 % and % dilutions of oxybuprocaine, 1.25 % and % dilutions of lidocaine, %, % and % dilutions of proparacaine hydrochloride  E.Coli proliferated in all dilutions of oxybuprocaine, % dilutions of lidocaine and %, % and % dilutions of proparacaine hydrochloride. EVALUATION OF THE ANTIMICROBIAL EFFECTS OF TOPICAL ANESTHETIC AGENTS

Pink: proliferation (+), Blue: proliferation (-) EVALUATION OF THE ANTIMICROBIAL EFFECTS OF TOPICAL ANESTHETIC AGENTS Proliferation profiles of S. aureus, E. faecalis, P. aeruginosa, S. pneumoniae, E. Coli, and C. Albicans

OxybuprocaineProparacaineLidocaine 0.2% 0.1%0.05%0.025%0.25%0.0125%0.0625%0.0312%5.0%2.5%1.25%0.625% S.aureus E.faecalis P.aeruginosa S.pneumoniae E.coli C.albicans (+): proliferation present, (-): no proliferation EVALUATION OF THE ANTIMICROBIAL EFFECTS OF TOPICAL ANESTHETIC AGENTS Proliferation profiles of S. aureus, E. faecalis, P. aeruginosa, S. pneumoniae, E. coli and, C. Albicans in different concentrations of topical anesthetics

Conclusions  Topical anesthetics that are used for sample collection in superficial ocular infections can cause false results in cultures by inhibating proliferations of microorganisms  Thus, it is important to know the effects of topical anesthetics and dilutions on bacterial proliferation EVALUATION OF THE ANTIMICROBIAL EFFECTS OF TOPICAL ANESTHETIC AGENTS

References 1.Mullin GS, Rubinfels RS. The antibacteriyel activty of topical anesthetics. Cornea 1997;16: Pelosini L, Treffene S, Hollick EJ. Antibacterial activity of preservative-free topical anesthetic drops in current use in ophthalmology departments. Cornea 2009;28: Kleinfeld J, Ellis PP. Effect of topical anaesthetics on growth of microorganisms. Arch Ophthalmol 1966;76: Silva MT, Sousa JCF, Polonia JJ, Macedo PM. Effects of local anaesthetics on bacterial cells. J Bacteriol 1979;137: Labetoulle M, Frau E, Offret H, Nordmann P. Non-preserved 1% lidocaine solution has less antibacterial properties than currently available anaesthetic eye-drops. Curr Eye Res 2002;25: Oguz H, Oguz E, Sobaci G, Aslan G. The effect of topical anesthetic proparacaine on normal conjunctival flora. T Klin J Ophthalmol 2000;9: Kleinfeld J, Ellis PP. Inhibition of Microorganisms by Topical Anesthetics. Appl Microbiol 1967;15: Badenoch PR, Coster DJ. Antimicrobial activity of topical anaesthetic preparations. Br J Ophthalmol 1982;66:364–7. EVALUATION OF THE ANTIMICROBIAL EFFECTS OF TOPICAL ANESTHETIC AGENTS