Fabric Challenge Assays: New Standards for the Evaluation of the Performance of Textiles Treated with Antimicrobial Agents

Textiles treated with antimicrobial agents are emerging as new strategies to reduce acquisition of healthcare-associated infections (HAIs). Essential to development/validation of these textiles are standard methods for the testing antimicrobial textile efficacy. Our laboratory has developed new testing methods, the fabric challenge assays, to recapitulate each transmission method and test the efficacy of antimicrobial textiles in a more “real world” simulation. 5 10 colony-forming units/ml (CFU/ml) MRSA suspensions were grown. 15 15 cm swatches of control, antimicrobial, hydrophobic barrier, and VTT003 fabric were inoculated with MRSA either by aerosol, splatter, or direct contact. Inoculated fabric was left at room temperature for 0, 30, or 60 min. Fabric was then transferred to buffer and shaken for 3 min at 400 rpm. A liquid suspension (0.1ml) was then plated onto blood agar, grown overnight at 37 C, and colonies were counted. In the aerosol test, at 0 min, VTT003 significantly reduced MRSA by 78.52610.26 % compared to control fabric. At 30 min, antimicrobial reduced MRSA levels by 91.486 8.52 %. In the splatter test, at 0 min, antimicrobial, hydrophobic barrier, and VTT003 fabrics reduced MRSA levels by 98.5661.44, 83.916 13.16, and 100.0060.03 %, respectively. At 30 min, hydrophobic barrier and VTT003 reduced levels by 82.63617.37 and 100.006 0.00 %, respectively. At 60min, hydrophobic barrier and VTT003 Manuscript received November 26, 2012; accepted for publication January 23, 2013; published online February 20, 2013. MedStar Health Research Institute, Laboratory of Clinical Investigations, Washington, D.C. 20010, United States of America. Weill Cornell Medical College, Department of Microbiology and Immunology, New York, New York 10021, United States of America. Copyright VC 2013 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. Pesticide Formulation and Delivery Systems: Innovating Legacy Products for New Uses STP 1558, 2013 Available online at www.astm.org DOI:10.1520/STP155820120184 Copyright by ASTM Int'l (all rights reserved); Fri Apr 19 11:12:09 EDT 2013 Downloaded/printed by Ben Favret (Vestagen) pursuant to License Agreement. No further reproductions authorized. abrogated MRSA levels. In the contact test, at 0 min, hydrophobic barrier and VTT003 reduced MRSA levels by 99.066 0.94 and 97.0862.92 %, respectively. At 30min, hydrophobic barrier and VTT003 reduced MRSA levels by 100.006 0.03 and 19.386 19.38 %, respectively. At 60 min, hydrophobic barrier and VTT003 abrogated MRSA levels. The fabric challenge assays are a novel method for evaluation of antimicrobial textile performance and should be considered in the development of standards and testing methods for all antimicrobial textiles intended for use in healthcare infection control strategies.