Broad spectrum killing of microorganisms with a one atmosphere uniform glow discharge plasma (OAUGDP)

Abstract

Summary form only given. We report the results of an ongoing interdisciplinary collaboration formed to assess the sterilizing capabilities of the one atmosphere uniform glow discharge plasma (OAUGDP). This glow discharge plasma is capable of operating at atmospheric pressure in air and provides antimicrobial active species to surfaces at room temperature as determined by viable plate counts. OAUGDP exposures have reduced log numbers of bacteria (S. aureus and E. coli), endospores (B. pumilus and B. subtilis) and yeast (S. cerevisiae and C. albicans) on various porous and non-porous surfaces. These include polypropylene, filter paper, paper strips, solid culture media, and glass. Experimental results showed a greater than or equal to 5 log 10 reduction in bacteria in times ranging from 15 to 60 sec. Additional tests were done with bacteria in sealed sterilization bags with similar results. However, when bacteria were embedded in agar, a greater than or equal to 5 log 10 reduction in numbers was seen in an extended time of 4 min. Plasma exposures of 5 min or less generated a greater than or equal to 5 log/sub 10/ reduction of bacterial endospores and yeast tested. All microorganisms tested exhibited a bi-phasic survival curve when plotted on a semi-log plot. Several proposed mechanisms of killing at room temperature by the OAUGDP are discussed.