Sakuragi T, Ishino H, Dan K
Department of Anesthesiology, School of Medicine, Fukuoka University, Japan.
Reg Anesth. 1996 May-Jun;21(3):239-42.
The rate of onset of antimicrobial activity of local anesthetics is unknown. Similarly, whether the activity is bactericidal or bacteriostatic is also unknown. The antimicrobial activity of local anesthetics with preservatives has not been studied. This study investigated the rate and potency of the antimicrobial activity of 0.125%, 0.25%, and 0.5% bupivacaine, 2.0% mepivacaine and 2.0% lidocaine with preservatives, and 2.0% lidocaine without preservatives on two strains of methicillin-resistant Staphylococcus aureus.
The pathogen was exposed to each local anesthetic for 1, 3, 6, 12, and 24 hours at room temperature. The inocula from these suspensions were diluted to 1:1,000 with physiological saline to inactivate the antimicrobial activity of the local anesthetics and then were cultured for 24 hours at 37 degrees C on agar plates.
Lower colony counts were observed with a 3-hour or longer exposure to 0.5% bupivacaine in both strains of S. aureus (P < .05). The 3-hour exposure reduced the count by approximately 60%, the 6-hour exposure by 70%, and the 24-hour exposure by more than 99%. The bactericidal activity was lowest with 0.125% bupivacaine and 2.0% mepivacaine.
Antimicrobial activity was observed shortly after exposure of S. aureus to local anesthetics and appeared to be bactericidal rather than bacteriostatic. However, the observed bactericidal activity, although it developed rapidly, may be insufficient to account for the low incidence of epidural infection related to epidural cannulation.
局部麻醉药抗菌活性的起效速率尚不清楚。同样，其活性是杀菌还是抑菌也未知。含防腐剂的局部麻醉药的抗菌活性尚未得到研究。本研究调查了含防腐剂的0.125%、0.25%和0.5%布比卡因、2.0%甲哌卡因和2.0%利多卡因以及不含防腐剂的2.0%利多卡因对两株耐甲氧西林金黄色葡萄球菌的抗菌活性速率和效力。
将病原体在室温下暴露于每种局部麻醉药中1、3、6、12和24小时。将这些悬液的接种物用生理盐水稀释至1:1000，以灭活局部麻醉药的抗菌活性，然后在37℃的琼脂平板上培养24小时。
在两株金黄色葡萄球菌中，0.5%布比卡因暴露3小时或更长时间后观察到菌落数减少（P < 0.05）。3小时暴露使菌落数减少约60%，6小时暴露减少70%，24小时暴露减少超过99%。0.125%布比卡因和2.0%甲哌卡因的杀菌活性最低。
金黄色葡萄球菌暴露于局部麻醉药后不久即观察到抗菌活性，且似乎是杀菌而非抑菌。然而，观察到的杀菌活性虽然发展迅速，但可能不足以解释与硬膜外置管相关的硬膜外感染发生率低的原因
