Comparison of effectiveness of skin antiseptics using conventional application with forceps and gauze swabs, single-use applicator, or by wetting skin with a low or high density of sebaceous glands.

Background: The preoperative application of skin antiseptics can be performed conventionally with sterile forceps and a sterile gauze swab or with a ready-made single-use applicator. Since the latter is more ecologically than the conventional procedure, an investigation into whether the application method influences the antiseptic efficacy is warranted. Method: The comparison was performed on the upper arm (low density of sebaceous glands) and forehead (high density of sebaceous glands) of volunteers according to test method 13 of the Association for Applied Hygiene for the certification of skin antiseptics in Germany. The antiseptic, 70% v/v propan-2-ol +2% w/v chlorhexidine digluconate (P/CHG), was applied either with the applicator, with forceps, or by gentle wetting without rub-in. After rub-in or wetting, samples were taken from the application area with sterile swabs, transferred into tryptic soy broth and plated onto tryptic soy agar. The reduction of the skin flora was calculated based on the number of colony forming units before and after antisepsis application. Additionally, the formulation P/CHG was compared with the reference standard 70% v/v propan-2-ol (P) for testing skin antiseptics in Germany. Results: There was no difference in antiseptic efficacy between the use of applicator or forceps. However, if the skin was only gentle wetted with the antiseptic, the efficacy was significantly lower than after rub-in with the applicator or forceps.In one trial, the antiseptic P/CHG tended to be more effective or, in another trial, was statistically significantly more effective than P when tested on skin with few sebaceous glands. Discussion: The results underline the necessity of thoroughly rubbing-in the antiseptic for preoperative skin antisepsis instead of merely wetting the skin. The literature confirms the higher efficacy of the P/CHG antiseptic compared to P (the reference for testing skin antiseptics in Germany), based on the criterion of rate of surgical site infections (SSI). Conclusion: According to the GRADE (Grading of Recommendations Assessment, Development and Evaluation)-based classification of evidence, the results presented here are of "high evidence". Thus, for preoperative skin antisepsis, P/CHG is to be used instead of alcohol-based formulations lacking CHG, due to the sustained efficacy of CHG. As the efficacy of applying the antiseptic with forceps and gauze swab or with single-use applicator does not differ on skin with few or many sebaceous glands, the single-use applicator should be preferred due to the guaranteed standardization of application, the time savings compared to the conventional method, and more favorable economic and ecological sustainability.