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The Effect of Commonly Used Local Anesthetic on Bacterial Growth
Zachary M Callahan1, Amity L Roberts2, Adrienne N Christopher1
1Division of Colorectal Surgery, Department of Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania.
Introduction:
Liposomal bupivacaine (LB) has emerged as a superior form of local anesthetic across numerous surgical subspecialties. The purpose of this study is to evaluate the ex-vivo antimicrobial effects of LB in comparison with traditional local anesthetics.
Methods:
A standardized inoculum of bacteria commonly associated with surgical site infection was inoculated into a suspension of 1% lidocaine, 0.25% bupivacaine, Exparel (proprietary liposomally packaged 1.3% bupivacaine), and normal saline as a growth control.
Results:
In all five bacteria tested, the medium inoculated with traditional local anesthetics reduced growth to a greater degree than LB-inoculated plates. Both conventional local anesthetics reduced the growth of all bacteria when compared with the control with the exception of methicillin-susceptible Staphylococcus aureus growth in bupivacaine. LB-inoculated plates had equivalent growth to the control in all plates with the exception of Escherichia coli plates which demonstrated superior growth.
Conclusions:
The results of this simple ex-vivo model suggest that the liposomal packaging of bupivacaine may decrease this local anesthetic's innate antibacterial properties.
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