Intramuscular Antibiotics Modify Infectious Outcomes in Contaminated, Ischemic Limbs

Area of Science:

• Trauma and Emergency Medicine
• Infectious Disease Research
• Pharmacology

Background:

• Tourniquets are vital for hemorrhage control in limb trauma but risk ischemic complications like infection.
• Intravenous antibiotic access is often limited in austere environments, complicating infection prevention.
• This study investigates intramuscular ertapenem at the tourniquet site to combat infection in contaminated wounds.

Purpose of the Study:

• To evaluate the efficacy of intramuscular ertapenem administered at the tourniquet site.
• To assess the impact on bacterial infection rates in a porcine model of contaminated crush laceration with ischemia.
• To determine the feasibility of localized antibiotic delivery in resource-limited settings.

Main Methods:

• A 24-hour porcine model with simulated crush laceration and bacterial inoculation (Staphylococcus aureus and Klebsiella pneumoniae).
• Tourniquet application for 4 hours, followed by intramuscular administration of either lidocaine (Control) or lidocaine with ertapenem.
• Continuous hemodynamic monitoring, wound cultures, and histopathology at multiple time points.

Main Results:

• Control group showed 100% deep tissue infection with both bacteria at 4 and 24 hours.
• Ertapenem group demonstrated a significant reduction in bacterial presence: Staphylococcus aureus in 50% (4h) and 33% (24h), Klebsiella pneumoniae in 33% (4h & 24h).
• Statistically significant differences (P < .05) in infection rates were observed between groups.

Conclusions:

• Intramuscular ertapenem at the tourniquet site effectively reduced bacterial infection rates by 67% in a contaminated, ischemic wound model.
• Localized antibiotic delivery via intramuscular injection alongside tourniquet application is a viable strategy.
• This approach holds potential for preventing infectious complications in combat-related injuries.