Background: This study presents a comparative investigation of the antimicrobial efficacy of the antiseptics PVP-iodine, triclosan, chlorhexidine, octenidine and polyhexanide used for pre-surgical antisepsis and antiseptic treatment of skin, wounds and mucous membranes based on internationally accepted standards.
Methods: MICs and MBCs were determined in accordance with DIN 58940-7 and 58940-8 using Staphylococcus aureus (including methicillin-resistant Staphylococcus aureus), Enterococcus faecalis (including vancomycin-resistant Enterococcus), Streptococcus pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Clostridium perfringens, Haemophilus influenzae and Candida albicans. The microbicidal efficacy was determined in accordance with DIN EN 1040 and 1275 using S. aureus, P. aeruginosa and C. albicans.
Results: For chlorhexidine, octenidine and polyhexanide, MIC(48) and MBC(24) ranged from 16 to 32 mg/L. Maximum values for triclosan ranged from 256 to 512 mg/L, with an efficacy gap against P. aeruginosa, while the maximum values of PVP-iodine were 1024 mg/L, with a gap against S. pneumoniae. Comparing the minimal effective concentrations, octenidine was most effective. After 1 min, only octenidine and PVP-iodine fulfil the requirements for antiseptics.
Conclusions: Tests under standardized and harmonized conditions help to choose the most efficacious agent. When a prolonged contact time is feasible, ranking of agents would be polyhexanide = octenidine > chlorhexidine > triclosan > PVP-iodine. This is consistent with the recommendations for antisepsis of acute wounds. Polyhexanide seems to be preferable for chronic wounds due to its higher tolerability. If an immediate effect is required, ranking would be octenidine = PVP-iodine>> polyhexanide > chlorhexidine > triclosan.