Objective: Use of single-dose antibiotic prophylaxis is associated with reduced antibiotic resistance, lower costs, and fewer problems with drug toxicity and superinfections. We tested the hypothesis that single doses of cefazolin are as effective as a 24-hour regimen of cefazolin in preventing surgical site infections in adults undergoing cardiac procedures.
Methods: This random, prospective, clinical study included 838 adult patients undergoing elective coronary artery bypass grafting, valve operations, or both. These patients were randomly given a single dose of cefazolin (2 g) or a 24-hour treatment (2-g initial dose, followed by 1 g every 8 hours). Investigators blinded to the drug regimen diagnosed wound infections according to Centers for Disease Control and Prevention criteria. Patient clinical and demographic characteristics were noted, with follow-up for 12 postoperative months. The primary objective was to compare the incidence of surgical infections between groups up to 12 months postoperatively.
Results: A total of 419 patients received single-dose cefazolin, and another 419 received the 24-hour treatment. Surgical site infection occurred in 35 (8.3%) patients receiving single doses and 15 (3.6%) patients administered the 24-hour treatment (P = .004). We identified no differences between groups for mortality or duration of hospitalization (preoperative hospitalization, intensive care unit stay, and hospitalization after surgical intervention). The microorganisms isolated showed a similar distribution in both groups. The germs isolated were gram-positive cocci in 86% of the surgical site infections.
Conclusions: Single-dose cefazolin used as antibiotic prophylaxis in cardiac surgery is associated with a higher surgical site infection rate than the 24-hour, multiple-dose cefazolin regimen.