A new Textile-Based Approach to Assess the Antimicrobial Activity of Volatiles

Textiles with antimicrobial properties are required in many areas but it is difficult to assess the effect with current assays based on the cultivation of microorganisms. Using confocal laser scanning microscopy (CLSM) we observed that the complex matrix of textiles provides an ideal niche for the adhesion of microorganisms because polyester fibres showed a high number of irregularly appearing notches. In another experiment with green fluorescent protein-labelled Staphylococcus epidermidis cells were found in these notches, tightly bound to the fibres. Staphylococcus cells shielded in the textile were not killed by conventional decontamination techniques like UV irradiation. Cultivation-dependent evaluation of bacterial survival after 10 minutes of irradiation indicated a good reduction of more than 99%, whereas fluorescent viability staining of cells, in combination with CLSM, displayed more than 5% survival. This latter sensitive assay can also be used to assess the activity of volatile antimicrobials. It was shown that volatiles produced by plant-associated bacteria (Pseudomonas chlororaphis and Paenibacillus polymyxa) irreversibly inhibited the growth of human-associated pathogens like Staphylococcus aureus and Candida albicans on textiles. This new approach enables the detection and evaluation of new volatile antimicrobials for their use in disinfection of garments