Postoperative wound infection, most often with, is of ubiquitous concern in surgical practice, occurring in an average of 1.5 to 5 percent of all procedures. The antimicrobial properties of
local anesthetics have been documented over the past 25 years by in vitro studies. This study evaluates the effects of
lidocaine preparations on in an in vivo setting. In a
wound infection model using live albino guinea pigs, inoculum was introduced for the reproducible bacterial colonization of clean
surgical wounds. One of two sites on the dorsum of each animal was infiltrated with a commercial
lidocaine preparation (with and without
epinephrine) prior to inoculation with (10 cfu/ml). The other site, inoculated with without preinfiltration with
lidocaine, served as the control. Cultures from the sites treated with
lidocaine were then compared with cultures from the control sites. All control sites had a consistent presence >or=10 cfu/ml, the threshold for bacterial inhibition of wound healing. Infiltration of the
wound with 2 ml of 2%
lidocaine prior to inoculation was associated with an average decrease in bacterial count of >70 percent ( n= 19). On the other hand, the addition of
epinephrine (1:100,000) to
lidocaine was associated with a 20-fold in bacterial counts compared with control values ( n= 10). This is the first study to demonstrate inhibition of by a
local anesthetic agent in an in vivo model of a
surgical wound. This information suggests a possible role for
local anesthetics in prophylaxis against
surgical wound infection.