In vitro antibacterial effects of topical local anesthetics.
BACKGROUND
The antibacterial activities of local anesthetics are recognized.


OBJECTIVE
To investigate in vitro the activity of topical local anesthetic ointments at clinical doses.


METHODS
The activity of two different local anesthetic ointments including lidocaine 5% and lidocaine/prilocaine 2.5% was tested against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Streptococcus pyogenes and Enterococcus faecalis by the disc-diffusion method. Sterile discs containing topical local anesthetic drugs were prepared taking into account the doses of ointments used in clinical practice. The validity of the methodology was confirmed using topical antibacterial mupirocin. The inhibition zones of the discs were measured.


RESULTS
Mupirocin inhibited all the bacteria. Both local anesthetic ointments were found to be most effective on E. coli, whereas they had no effects on P. aeruginosa. Lidocaine 5% revealed antibacterial activity against S. aureus, S. epidermidis, E. coli, S. pyogenes and E. faecalis, but lidocaine/prilocaine 2.5% showed no activity on E. faecalis and inhibited S. pyogenes only at double doses. It was also observed that the antibacterial activity was in a dose-dependent manner.


CONCLUSIONS
In the light of these findings, it might be concluded that topical local anesthetic ointments in routine settings may have a preventive role against some bacteria.
Sedef Gocmen
J
J
Department of Microbiology and Clinical Microbiology, Faculty of Medicine, Kirikkale University, Kirikkale, Turkey. jsedef@yahoo.com
Buyukkocak
Unase
U
Caglayan
Osman
O
Aksoy
Altan
A
D000279:Administration, Cutaneous; D000779:Anesthetics, Local / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004359:Drug Therapy, Combination; D013293:Enterococcus faecalis / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D008012:Lidocaine / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests / Q000379:methods*; D016712:Mupirocin / Q000494:pharmacology*; D011318:Prilocaine / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D015203:Reproducibility of Results; D013211:Staphylococcus aureus / Q000187:drug effects; D013212:Staphylococcus epidermidis / Q000187:drug effects; D013297:Streptococcus pyogenes / Q000187:drug effects
D000779:Anesthetics, Local; D000900:Anti-Bacterial Agents; D011318:Prilocaine; D008012:Lidocaine; D016712:Mupirocin