title: Comparison of two radio-frequency plasma sterilization processes using microspot evaluation of microbial inactivation.
abstract: In this study, we evaluated gas plasma surface sterilization methods in a specific sterilizer. We have introduced a new monitoring method using 0.4 microm pore size membranes, which in this study gave the information corresponding to 3000 exposed biological indicators per treatment cycle. This enabled us to compare the fraction of inoculates that showed no growth after exposure for 30 different locations in the chamber, and hereby identify weak and strong spots in the chamber with regard to sporicidal effect. Membranes were also used to expose a broad spectrum of soil bacteria for plasma treatment at four different conditions. The organisms were identified using PCR and sequencing. The test showed that Bacillus stearothermophilus spores were inactivated at the slowest rate among the tested microorganisms. Further alpha-proteobacteria (Gram negative) seemed more sensitive than the rest of the tested organisms. The microspot evaluation approach has been a most useful tool in the assessment of sterilization performance in sterilizers that do not have clear measurable parameters related to the sterilization.
authors.affiliation: The National Centre for Antimicrobials and Hospital Hygiene, Statens Serum Institut, 5 Artillerivej, 2300 Copenhagen S, Denmark. ksl@ssi.dk
authors.forename: Klaus S
authors.initials: KS
authors.lastname: Lassen
authors.forename: Jens E
authors.initials: JE
authors.lastname: Johansen
authors.forename: Reinar
authors.initials: R
authors.lastname: Grün
mesh_terms: D001672:Biocompatible Materials; D001411:Geobacillus stearothermophilus; D006861:Hydrogen Peroxide; D010463:Peracetic Acid; D011846:Radio Waves; D013171:Spores, Bacterial; D013242:Sterilization
chemical_list: D001672:Biocompatible Materials; D006861:Hydrogen Peroxide; D010463:Peracetic Acid