Published in:Applied and Environmental Microbiology
Language:
English
DOI:
10.1128/aem.00583-12
ISSN:
0099-2240;
1098-5336
Origination:
Footnote:
Description:
<jats:title>ABSTRACT</jats:title>
<jats:p>
Physical cold atmospheric surface microdischarge (SMD) plasma operating in ambient air has promising properties for the sterilization of sensitive medical devices where conventional methods are not applicable. Furthermore, SMD plasma could revolutionize the field of disinfection at health care facilities. The antimicrobial effects on Gram-negative and Gram-positive bacteria of clinical relevance, as well as the fungus
<jats:named-content content-type="genus-species">Candida albicans</jats:named-content>
, were tested. Thirty seconds of plasma treatment led to a 4 to 6 log
<jats:sub>10</jats:sub>
CFU reduction on agar plates.
<jats:named-content content-type="genus-species">C. albicans</jats:named-content>
was the hardest to inactivate. The sterilizing effect on standard bioindicators (bacterial endospores) was evaluated on dry test specimens that were wrapped in Tyvek coupons. The experimental
<jats:italic>D</jats:italic>
<jats:sub>23</jats:sub>
<jats:sub>°</jats:sub>
<jats:sub>C</jats:sub>
values for
<jats:named-content content-type="genus-species">Bacillus subtilis</jats:named-content>
,
<jats:named-content content-type="genus-species">Bacillus pumilus</jats:named-content>
,
<jats:named-content content-type="genus-species">Bacillus atrophaeus</jats:named-content>
, and
<jats:named-content content-type="genus-species">Geobacillus stearothermophilus</jats:named-content>
were determined as 0.3 min, 0.5 min, 0.6 min, and 0.9 min, respectively. These decimal reduction times (
<jats:italic>D</jats:italic>
values) are distinctly lower than
<jats:italic>D</jats:italic>
values obtained with other reference methods. Importantly, the high inactivation rate was independent of the material of the test specimen. Possible inactivation mechanisms for relevant microorganisms are briefly discussed, emphasizing the important role of neutral reactive plasma species and pointing to recent diagnostic methods that will contribute to a better understanding of the strong biocidal effect of SMD air plasma.
</jats:p>