Disinfection of meticillin-resistant Staphylococcus aureus and Staphylococcus epidermidis biofilms using a remote non-thermal gas plasma

Summary The effective disinfection of hospital surfaces is recognised as an important factor in preventing hospital-acquired infections. The purpose of this study was to quantify the disinfection rate of a novel gas plasma system on clinically relevant biofilms. Clinical isolates of Staphylococcus epidermidis and meticillin-resistant Staphylococcus aureus (MRSA) were grown as biofilms on glass surfaces and tested in a disinfection container remote from the plasma source. The strains used in this study were known to produce substantial quantities of biofilm and average log 10 counts were 9.0 and 9.1 cfu/cm 2 for S. epidermidis and MRSA respectively. Counts were reduced by between 4 and 4.5 log 10 after 1 h of exposure for MRSA and S. epidermidis respectively. More prolonged treatment in the case of MRSA biofilms resulted in a 5.5 log 10 reduction after 90 min. Biofilm samples were also placed in medical device packaging bags and similar rates of disinfection were observed.