Electromagnetic augmentation of antibiotic efficacy in infection of orthopaedic implants.
Infection of orthopaedic implants is a significant problem, with increased antibiotic resistance of adherent 'biofilm' bacteria causing difficulties in treatment. We have investigated the in vitro effect of a pulsed electromagnetic field (PEMF) on the efficacy of antibiotics in the treatment of infection of implants. Five-day biofilms of Staphylococcus epidermidis were grown on the tips of stainless-steel pegs. They were exposed for 12 hours to varying concentrations of gentamicin or vancomycin in microtitre trays at 37 degrees C and 5% CO2. The test group were exposed to a PEMF. The control tray was not exposed to a PEMF. After exposure to antibiotic the pegs were incubated overnight, before standard plating onto blood agar for colony counting. Exposure to a PEMF increased the effectiveness of gentamicin against the five-day biofilms of Staphylococcus epidermidis. In three of five experiments there was reduction of at least 50% in the minimum biofilm inhibitory concentration. In a fourth experiment there was a two-log difference in colony count at 160 mg/l of gentamicin. Analysis of variance (ANOVA) confirmed an effect by a PEMF on the efficacy of gentamicin which was significant at p < 0.05. There was no significant effect with vancomycin.
Pickering
S A W
SA
Academic Department of Orthopaedic and Fracture Surgery, Queen's Medical Centre, Nottingham, England, UK.
Bayston
R
R
Scammell
B E
BE
D000704:Analysis of Variance; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D018441:Biofilms / Q000187:drug effects*; D015169:Colony Count, Microbial; D004574:Electromagnetic Fields; D005839:Gentamicins / Q000627:therapeutic use; D006801:Humans; D008826:Microbial Sensitivity Tests; D011183:Postoperative Complications / Q000188:drug therapy*; D016459:Prosthesis-Related Infections / Q000188:drug therapy*; D013203:Staphylococcal Infections / Q000188:drug therapy*; D013212:Staphylococcus epidermidis / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D014640:Vancomycin / Q000627:therapeutic use
D000900:Anti-Bacterial Agents; D005839:Gentamicins; D014640:Vancomycin