Effects of olanexidine gluconate on preoperative skin preparation: an experimental study in cynomolgus monkeys

Abstract

Purpose: To determine the bactericidal efficacy of a new topical antiseptic for preoperative skin preparation, olanexidine gluconate (development code: OPB-2045G), against transient or resident bacterial flora on the skin of cynomolgus monkeys.

Methodology: After measuring baseline bacterial counts on test sites marked on the abdomens, we applied olanexidine, chlorhexidine or povidone-iodine. After 10 min (fast-acting effect) and 6 h (long-lasting effect), bacterial counts were measured again and log10 reductions were calculated. In addition, we determined the bactericidal effects on the skin contaminated with blood before or after applying the antiseptics.

Results: In the non-blood-contaminated condition, the mean log10 reductions of olanexidine at doses of 1-2 % were significantly higher than those of saline (negative control), but did not significantly differ from those of 0.5 % chlorhexidine and 10 % povidone-iodine at either time point. But olanexidine was significantly more effective at both time points than chlorhexidine and povidone-iodine when applied after the site was contaminated with blood. Olanexidine was also significantly more effective than chlorhexidine and as effective as or more effective than povidone-iodine at both time points when skin was contaminated with blood after the antiseptics were applied.

Conclusion: The bactericidal effects of olanexidine were comparable to those of commercial antiseptics such as chlorhexidine and povidone-iodine in non-blood-contaminated conditions. More importantly, the effect of olanexidine was hardly affected by blood unlike commercial antiseptics. Thus, it is considered that olanexidine has a favourable property for skin preparation in various types of surgical treatments.

Fig. 1.

Chemical structure of olanexidine gluconate.

Fig. 2.

Changes in viable bacterial counts from baseline (white columns) to 10 min (black columns) and to 6 h (grey column) after antiseptic application against skin flora of cynomolgus monkeys in clean condition. Each column and vertical bar represents the mean and sd for eight test sites. Values not sharing a common letter at same time point differ significantly at P<0.05 by Tukey’s multiple comparisons test.

Fig. 3.

Changes in viable bacterial counts from baseline (white column) to 10 min (black column) to 6 h (hatched column) after antiseptic application on the skin flora of cynomolgus monkeys in the contaminated condition; blood contamination before antiseptic applied (a) and blood contamination after antiseptic applied (b). Each column and vertical bar represents the mean and sd for eight test sites. Values not sharing a common letter at same time point differ significantly at P<0.05 by Tukey’s multiple comparisons test.