The antimicrobial activity of bupivacaine, lidocaine and mepivacaine against equine pathogens: An investigation of 40 bacterial isolates.

The research article primarily focuses on investigating the antibacterial effect of local anesthetics used in horses. The study specifically examines the action of bupivacaine, lidocaine, and mepivacaine on various equine bacteria.

Objective and Importance of the Study

• Horses often experience lameness – a health problem that commonly necessitates the use of local anaesthetics by equine practitioners. As these anesthetics are administered through injections, there’s a risk that bacteria may enter the punctured tissues, potentially causing local infections. As such, the study aimed to examine whether local anesthetics could inhibit or possibly eliminate the harmful bacteria which can infiltrate soft tissues or the synovial space during injection.

Research Methodology

• The study utilized commercially available solutions of the local anesthetics bupivacaine, lidocaine, and mepivacaine, and tested their antimicrobial activity against a variety of 40 equine clinical bacterial isolates.
• The bacterial genera tested comprised of Actinobacillus, Corynebacterium, Enterobacter, Escherichia, Pseudomonas, Rhodococcus, Staphylococcus, and Streptococcus.
• The research methodologies employed included the determination of Minimum Inhibitory Concentrations (MICs) and Minimum Bactericidal Concentrations (MBCs) through the broth microdilution method.

Research Findings

• The research demonstrated that the concentrations of bupivacaine, lidocaine, and mepivacaine present in commercial solutions were successful in inhibiting the growth of 93%, 93%, and 80% of the bacterial isolates tested, respectively. For most (80%) of the inhibited isolates, the concentrations were also found to be bactericidal (bacteria-killing).
• Furthermore, the study revealed that these local anesthetics had antimicrobial properties against equine bacteria at the concentrations typically used in clinical settings.

Implications of the Study

• The results of this study suggest that local anaesthetics possess antimicrobial activity and could potentially mitigate the risk of bacterial infections introduced through needle punctures during their administration.
• Nevertheless, the study also points out that despite their antimicrobial properties, the use of local anesthetics should not replace thorough antiseptic preparation prior to the injection procedures. This ensures an extra layer of protection against potential bacterial infections.