Evaluation of antimicrobial activity of a polyhexamethylène biguanide-coated textile by monitoring both baterial growth (ISO 20743/2005 Standard) and viability (live/dead baclight kit)
Résumé
Antimicrobial textiles (65% cotton - 35% polyester) were functionalized using a patented technology that combines an antimicrobial molecule - polyhexamethylene biguanide (PHMB) and a precipitating agent - sodium laurylsulphate. Surface characterization was performed by x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry, and both techniques made clear signatures of PHMB at the top surface of treated textiles. Washing led to a strong decrease of PHMB concentration at the surface. Comparison of textile surface analysis and antimicrobial tests indicated that the amount of PHMB at its extreme surface of textiles after five or 10 industrial washings was sufficient to inhibit Listeria innocua but not Pseudomonas aeruginosa growth. The viability of L. innocua cells after contact with PHMB-treated textile after one industrial washing was estimated using the Live/Dead BacLight kit (Molecular Probes, Eugene, OR): the combination of epifluorescence microscopy observations coupled with classic enumeration allowed detection of the presence of viable but nonculturable cells.