TY - JOUR AU - Mai-Prochnow, A AU - Clauson, M AU - Hong, J AU - Murphy, AB Y2 - 2020/12/22 Y1 - 2016/12/09 SN - 2045-2322 UR - http://hdl.handle.net/11343/258102 AB - Cold atmospheric-pressure plasma (CAP) is a relatively new method being investigated for antimicrobial activity. However, the exact mode of action is still being explored. Here we report that CAP efficacy is directly correlated to bacterial cell wall thickness in several species. Biofilms of Gram positive Bacillus subtilis, possessing a 55.4 nm cell wall, showed the highest resistance to CAP, with less than one log10 reduction after 10 min treatment. In contrast, biofilms of Gram negative Pseudomonas aeruginosa, possessing only a 2.4 nm cell wall, were almost completely eradicated using the same treatment conditions. Planktonic cultures of Gram negative Pseudomonas libanensis also had a higher log10 reduction than Gram positive Staphylococcus epidermidis. Mixed species biofilms of P. aeruginosa and S. epidermidis showed a similar trend of Gram positive bacteria being more resistant to CAP treatment. However, when grown in co-culture, Gram negative P. aeruginosa was more resistant to CAP overall than as a mono-species biofilm. Emission spectra indicated OH and O, capable of structural cell wall bond breakage, were present in the plasma. This study indicates that cell wall thickness correlates with CAP inactivation times of bacteria, but cell membranes and biofilm matrix are also likely to play a role. LA - English PB - NATURE PUBLISHING GROUP T1 - Gram positive and Gram negative bacteria differ in their sensitivity to cold plasma DO - 10.1038/srep38610 IS - Scientific Reports VL - 6 IS - 1 L1 - /bitstream/handle/11343/258102/PMC5146927.pdf?sequence=1&isAllowed=y ER -