When should old therapies be abandoned? A modern look at old studies on topical ampicillin

Objective. We sought to determine whether topical ampicillin can reduce the rate of wound infections in clean contaminated surgical wounds (appendectomy, colorectal surgery). Method. All randomized controlled trials examining the use of topical ampicillin in appendectomy and colorectal surgery published in English were identified via a Medline, Advanced Medline, and Cochraine Controlled Trials Register search and a meta-analysis performed. Results. Topical ampicillin vs. no antibiotic prophylaxis in clean contaminated wounds significantly reduced surgical wound infection rates (Odds Ratio (OR) = 0.084, 95% CI, 0.04-0.16, P < 0.0001). Topical ampicillin vs. no antibiotic prophylaxis in contaminated wounds also reduced surgical wound infection (OR = 0.262, 95% CI, 0.14-0.51, P < 0.0001). Topical ampicillin combined with systemic antibiotics vs. systemic antibiotics alone did not reduce surgical wound infection rate (OR = 0.927, 95% CI, 0.27-1.72, P = 0.90). Conclusion. Topical ampicillin significantly reduces the rate of surgical wound infections in clean contaminated surgery. A significant but smaller effect is seen in appendectomies where the appendix is gangrenous or perforated. Topical ampicillin did not confer any additional benefit when systemic antibiotics are used. While ampicillin may no longer be an effective agent, topical application of antibiotics is effective. Summary. A meta-analysis of studies using topical ampicillin for the prevention of infection in clean contaminated wound suggests that topical ampicillin is effective, but no incremental benefit is seen with systemic antibiotics.