Use of Dacron as an Alternative Carrier for Evaluating Oxidizing Sterilants in the AOAC Sporicidal Test

Abstract

The AOAC sporicidal method (966.04) recommends the use of porcelain penicylinders and black waxed silk sutures as carriers for demonstrating the sporicidal activity of sterilants. However, the silk carriers are not suitable for evaluating the sporicidal efficacy of oxidizing agents, and an inert polyester material (Dacron) is recommended as an alternative. Dacron provides an equivalent microbial and physical challenge to silk. Microbiologically, both materials demonstrated similar HCl resistance, which is required by the AOAC test, as well as equivalent spore loading and spore wash-off. Electron microscopy showed that both materials present the same braided microstructure, providing an equivalent physical challenge to the test sterilant. Dacron was more consistent than silk, and did not require extraction prior to spore loading. The extraction method for black waxed silk was variable and incomplete, which may compromise the activity of oxidizing sterilants and add to method variability. Silk was also structurally altered in the presence of oxidizing sterilants and increased sterilant degradation. Dacron did not affect the sterilant and was inert in the presence of oxidizing agents. Dacron sutures are proposed as inert alternatives to silk for evaluating the sporicidal efficacy of oxidizing agents.

Guideline for Disinfection and Sterilization of Prion-Contaminated Medical Instruments

“…or ME7, bovine spongiform encephalopathy prion strain 6PB1 or 301V, vCJD prion, and sporadic CJD prion), prion concentration, prion detection, 34 tissue or composition of the brain material tested (intact brain tissue, brain homogenates, or partially purified preparations), animals tested, surfaces tested (eg, plastic or stainless steel), testing method (in vivo or vitro [eg, Western blot]), duration of follow-up of inoculated animals, exposure container (eg, open or closed), method of calculating log 10 reductions in infectivity, concentration of the disinfectant at the beginning and end of the experiment, cycle parameters of the sterilizer, type of sterilizer (eg, gravity vs vacuum or porous steam sterilizers), and exposure conditions. Methodological issues have been found to significantly affect the antimicrobial testing results for all pathogens [71][72][73][74][75][76] and likely explain the varying results seen with various chemical disinfection methods (eg, use of sodium hydroxide [NaOH] or chlorine) and sterilization methods (eg, steam sterilization at 134ЊC for 18 minutes vs exposure to NaOH plus steam sterilization). Despite these limitations, there is a consistent pattern in the results.…”

Evaluation of AISI Type 304 stainless steel as a suitable surface material for evaluating the efficacy of peracetic acid-based disinfectants against Clostridium difficile spores

“…Allowances for alternative carrier materials have been made when it has been determined that the material specified in the standard method is not a suitable predictor of real life efficacy. For example, Dacron® suture material was proposed as an alternative to silk suture material for evaluating the sporicidal efficacy of PAA-based disinfectants agents because silk caused PAA degradation [ 5 , 6 ]. As a result of this research, AOAC International and the EPA accept the use of Dacron®, instead of silk, as a carrier material for PAA-based disinfectants for the AOAC Sporicidal Activity Test [ 7 , 8 ].…”