Evaluation of alcohol wipes used during aseptic manufacturing

During aseptic manufacturing and specifically during the transfer of items into an isolator, disinfection of surfaces is essential for reducing the risk of final product contamination. Surface disinfection can be carried out by a variety of methods, however the most accepted current practice is a combination of spraying with 70% alcohol and wiping. The aim of this study was to evaluate the effectiveness of two wipe systems by determining their ability to remove, kill and transfer bacterial contaminants from standardized surfaces. The protocol used to achieve these objectives was based on a newly published method specifically designed to test wipes. Alcohol impregnated wipes performed better at reducing microbial bioburden than the alcohol spray/dry wipe applications. Impregnated wipes drastically reduced (1-2 log(10) reduction) a small bioburden (approx. 2 log(10)) of spores of Bacillus subtilis and methicillin-resistant Staphylococcus aureus from the surface, but failed to remove (< 0.2 log(10) reduction) Staphylococcus epidermidis. The alcohol spray/dry wipes did not manage to remove (< 0.2 log(10) reduction) spore or bacterial bioburden from surfaces and was able to transfer some viable micro-organisms to other surfaces. Both wipe types showed poor antimicrobial efficacy (< 1 log(10) reduction) against the test bacteria and spores. As far as the authors are aware this is the first time that such a practical study has been reported and our results suggest that the best wipes for surface disinfection in aseptic units are the alcohol (IPA) impregnated wipes when compared with the dry wipes sprayed with alcohol. The impregnated wipes performed better than the dry wipes sprayed with alcohol and should be used for surface disinfection in aseptic units.