Bakteriers multiresistens og triclosan

Abstract

Triclosan er et biocid som anvendes i mange forbrugsprodukter såsom sæber, tandpasta og husholdningsartikler. I denne rapport påvises det, at triclosan selekterer antibiotikaresistente E. coli, og i særdeleshed resistens for tetracycline. Denne resistenssammenhæng kan sandsynligvis relateres til en øget effluxpumpeaktivitet i AcrAB. Det vises at den øgede aktivitet i AcrAB, som formodentlig skyldes en overekspression af acrAB eller at en af de positive regulatorer af acrAB, soxS og marA, giver de resistente kloner selektive fordele i miljøer med subletale triclosan koncentrationer. Det vises også at resistensmekanismen nedsætter mutanternes vækstfrekvens med op til 50 % i forhold til vildtypen.

Triclosan is a biocide added to many consumer products such as soap, toothpaste and household articles. In this report it is proven that triclosan selects antibiotic resistant E. coli, and resistance for tetracycline in particular. This cross-resistance can probably be related to increased efflux activity in AcrAB. It is shown how the increased activity in AcrAB, most likely caused by overexpression of acrAB or of one of the positive regulators of acrAB, soxS and marA, provides the resistant clones selective advantages in environments with sublethal concentrations of triclosan. It is also shown how the resistance mechanism decreases the mutants’ growth frequency with up to 50 % compared to the wild-type.