Analysis of in vitro antimicrobial activity of antiseptics products by means of time kill assay

Abstract

Many chemicals (alcohol, iodophor, chlorhexidine, etc) are used in laboratories and industries. Unlike disinfectants, no specific norms and criteria have been standardized for evaluating the antiseptics activity. This study analyzed the antimicrobial activity of antiseptics using Time Kill Test (Hobson & Bolsen). This assay assessed the evolution of a population of aerobic microorganisms in a specific period of time when tested against antimicrobial agents. Two different recovery methodologies were evaluated: membrane filtration and pour plate technique The membrane filtration assay was less sensitive. Pour plate technique showed high sensitivity with high colonies counts. Of 25 samples of products analyzed, only the chlorhexidine digluconate-based antiseptics were unsatisfactory, showing no efficacy on all reference micro-organisms strains, and corresponded to 20 % of analyzed samples. However, they were efficacious against clinical strains. Therefore, these products should be used with caution and further studies are needed, as data on its efficacy have still been scarce. These findings might give support to the health surveillance and public health in establishing the future legislation, as these products have been available on the market, but without following any specific legislation.