TY - JOUR
T1 - Eradication of Pseudomonas aeruginosa Biofilms by Atmospheric Pressure Non-Thermal Plasma
AU - Alkawareek, Mahmoud Y.
AU - Algwari, Qais Th.
AU - Laverty, Garry
AU - Gorman, Sean P.
AU - Graham, William G.
AU - O'Connell, Deborah
AU - Gilmore, Brendan F.
PY - 2012/8/31
Y1 - 2012/8/31
N2 - Bacteria exist, in most environments, as complex, organised communities of sessile cells embedded within a matrix of self-produced, hydrated extracellular polymeric substances known as biofilms. Bacterial biofilms represent a ubiquitous and predominant cause of both chronic infections and infections associated with the use of indwelling medical devices such as catheters and prostheses. Such infections typically exhibit significantly enhanced tolerance to antimicrobial, biocidal and immunological challenge. This renders them difficult, sometimes impossible, to treat using conventional chemotherapeutic agents. Effective alternative approaches for prevention and eradication of biofilm associated chronic and device-associated infections are therefore urgently required. Atmospheric pressure non-thermal plasmas are gaining increasing attention as a potential approach for the eradication and control of bacterial infection and contamination. To date, however, the majority of studies have been conducted with reference to planktonic bacteria and rather less attention has been directed towards bacteria in the biofilm mode of growth. In this study, the activity of a kilohertz-driven atmospheric pressure non-thermal plasma jet, operated in a helium oxygen mixture, against Pseudomonas aeruginosa in vitro biofilms was evaluated. Pseudomonas aeruginosa biofilms exhibit marked susceptibility to exposure of the plasma jet effluent, following even relatively short (similar to 10's s) exposure times. Manipulation of plasma operating conditions, for example, plasma operating frequency, had a significant effect on the bacterial inactivation rate. Survival curves exhibit a rapid decline in the number of surviving cells in the first 60 seconds followed by slower rate of cell number reduction. Excellent anti-biofilm activity of the plasma jet was also demonstrated by both confocal scanning laser microscopy and metabolism of the tetrazolium salt, XTT, a measure of bactericidal activity.
AB - Bacteria exist, in most environments, as complex, organised communities of sessile cells embedded within a matrix of self-produced, hydrated extracellular polymeric substances known as biofilms. Bacterial biofilms represent a ubiquitous and predominant cause of both chronic infections and infections associated with the use of indwelling medical devices such as catheters and prostheses. Such infections typically exhibit significantly enhanced tolerance to antimicrobial, biocidal and immunological challenge. This renders them difficult, sometimes impossible, to treat using conventional chemotherapeutic agents. Effective alternative approaches for prevention and eradication of biofilm associated chronic and device-associated infections are therefore urgently required. Atmospheric pressure non-thermal plasmas are gaining increasing attention as a potential approach for the eradication and control of bacterial infection and contamination. To date, however, the majority of studies have been conducted with reference to planktonic bacteria and rather less attention has been directed towards bacteria in the biofilm mode of growth. In this study, the activity of a kilohertz-driven atmospheric pressure non-thermal plasma jet, operated in a helium oxygen mixture, against Pseudomonas aeruginosa in vitro biofilms was evaluated. Pseudomonas aeruginosa biofilms exhibit marked susceptibility to exposure of the plasma jet effluent, following even relatively short (similar to 10's s) exposure times. Manipulation of plasma operating conditions, for example, plasma operating frequency, had a significant effect on the bacterial inactivation rate. Survival curves exhibit a rapid decline in the number of surviving cells in the first 60 seconds followed by slower rate of cell number reduction. Excellent anti-biofilm activity of the plasma jet was also demonstrated by both confocal scanning laser microscopy and metabolism of the tetrazolium salt, XTT, a measure of bactericidal activity.
KW - BACTERIAL BIOFILMS
KW - JET
KW - IN-VITRO
KW - NOSOCOMIAL INFECTIONS
KW - INACTIVATION
KW - BARRIER DISCHARGE PLASMA
KW - DISEASE
KW - STERILIZATION
KW - MECHANISMS
KW - PERSISTER CELLS
UR - http://www.scopus.com/inward/record.url?scp=84865634732&partnerID=8YFLogxK
U2 - 10.1371/journal.pone.0044289
DO - 10.1371/journal.pone.0044289
M3 - Article
SN - 1932-6203
VL - 7
JO - PLoS ONE
JF - PLoS ONE
IS - 8
M1 - ARTN e44289
ER -