Eradication of multidrug-resistant pseudomonas biofilm with pulsed electric fields.
Biofilm formation is a significant problem, accounting for over eighty percent of microbial infections in the body. Biofilm eradication is problematic due to increased resistance to antibiotics and antimicrobials as compared to planktonic cells. The purpose of this study was to investigate the effect of Pulsed Electric Fields (PEF) on biofilm-infected mesh. Prolene mesh was infected with bioluminescent Pseudomonas aeruginosa and treated with PEF using a concentric electrode system to derive, in a single experiment, the critical electric field strength needed to kill bacteria. The effect of the electric field strength and the number of pulses (with a fixed pulse length duration and frequency) on bacterial eradication was investigated. For all experiments, biofilm formation and disruption were confirmed with bioluminescent imaging and Scanning Electron Microscopy (SEM). Computation and statistical methods were used to analyze treatment efficiency and to compare it to existing theoretical models. In all experiments 1500 V are applied through a central electrode, with pulse duration of 50 μs, and pulse delivery frequency of 2 Hz. We found that the critical electric field strength (Ecr) needed to eradicate 100-80% of bacteria in the treated area was 121 ± 14 V/mm when 300 pulses were applied, and 235 ± 6.1 V/mm when 150 pulses were applied. The area at which 100-80% of bacteria were eradicated was 50.5 ± 9.9 mm(2) for 300 pulses, and 13.4 ± 0.65 mm(2) for 150 pulses. 80% threshold eradication was not achieved with 100 pulses. The results indicate that increased efficacy of treatment is due to increased number of pulses delivered. In addition, we that showed the bacterial death rate as a function of the electrical field follows the statistical Weibull model for 150 and 300 pulses. We hypothesize that in the clinical setting, combining systemic antibacterial therapy with PEF will yield a synergistic effect leading to improved eradication of mesh infections.
Division of Plastic and Reconstructive Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114.
Saiqa I
SI
Khan
Department of Computer Science, Tel Aviv University, Tel Aviv, Israel.
Gaddi
G
Blumrosen
Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts 02114.|Department of Dermatology, Harvard Medical School, Boston, Massachusetts 02115.
Daniela
D
Vecchio
Center for Engineering in Medicine, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, and the Shriners Burns Hospital, Boston, Massachusetts 02114.|Porter School of Environmental Studies, Tel Aviv University, Tel Aviv, Israel.
Alexander
A
Golberg
Division of Plastic and Reconstructive Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114.
Michael C
MC
McCormack
Center for Engineering in Medicine, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, and the Shriners Burns Hospital, Boston, Massachusetts 02114.|Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey 08854.
Martin L
ML
Yarmush
Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts 02114.|Department of Dermatology, Harvard Medical School, Boston, Massachusetts 02115.|Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts 02139.
Michael R
MR
Hamblin
Division of Plastic and Reconstructive Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114.
William G
WG
Austen
D018441:Biofilms / Q000254:growth & development*; D004203:Disinfection / Q000379:methods*; D024901:Drug Resistance, Multiple, Bacterial; D004560:Electricity; D004864:Equipment and Supplies / Q000382:microbiology*; D008163:Luminescent Measurements; D050296:Microbial Viability; D008855:Microscopy, Electron, Scanning; D061848:Optical Imaging; D011126:Polypropylenes; D011550:Pseudomonas aeruginosa / Q000502:physiology*
D011126:Polypropylenes
biofilm; eradication of multidrug resistant infections; irreversible electroporation; medical device disinfection; pulsed electric fields; treatment of mesh infection