Influence of human wound exudate on the bactericidal efficacy of antiseptic agents in quantitative suspension tests on the basis of European Standards (DIN EN 13727)

Abstract

The antimicrobial efficacy of antiseptics used in wound management is tested in vitro under standardised conditions according to DIN EN 13727, with albumin and sheep erythrocytes used as organic challenge. However, these testing conditions do not adequately simulate the wound bed environment. Thus, the aim of this study was to compare the efficacy of different antiseptics such as octenidine dihydrochloride (OCT), chlorhexidine digluconate (CHX), polyhexamethylene biguanide (PHMB), and povidone-iodine under challenge with human wound exudate instead of standardised organic load in an in vitro setting according to DIN EN 13727. Moreover, protein contents, pH, and temperature were compared with standardised testing conditions. The tested antiseptic agents were reduced to different extents based on their bactericidal efficacy, when challenged with human wound exudate compared with standardised conditions. Overall, 0.10% OCT showed the highest effects reaching full efficacy after 30 seconds. CHX and PHMB were the least efficient. Next to the protein content, other components of wound exudate, such as the microflora, seem to influence the efficacy of antiseptics. In summary, the optimisation of in vitro testing conditions in future applications, to more adequately simulate the wound bed environment, will allow a more realistic picture on the potential performance of antiseptics in clinical practice.

Keywords: DIN EN 13727; antiseptics; chronic wounds; organic challenge; wound exudate.