Efficacy of a topical antibiotic irrigant in decreasing or eliminating bacterial contamination in surgical wounds.

Using a simple in vitro system, the authors showed that colony counts of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas species can be reduced by 12%-56% with saline irrigation; the reduction of colony numbers, however, especially for S. aureus, was not always statistically significant. However, even if it were statistically significant, the amount of reduction would not be clinically significant. A topical antibiotic irrigant containing bacitracin/neomycin was effective against S. aureus, S. epidermidis-, and E. coli-treated agar plates. Except for a single plate containing Pseudomonas organisms, the growth of Pseudomonas colonies was also prevented by antibiotic irrigation. Tissue samples of muscle, fat, and bone obtained during operation showed antibiotic levels comparable with, and in most cases greater than, those found in the blood agar plates. These data may be clinically significant and suggest that bacitracin/neomycin irrigation can be safely used to reduce the incidence of postoperative infection.