Regional antibiotic delivery for the treatment of experimental prosthetic graft infections.
OBJECTIVE
To evaluate the efficacy of antibiotic-impregnated polymethylmethacrylate (PMMA) beads in eradication of an arterial prosthetic graft methicillin-resistant Staphylococcus aureus (MRSA) biofilm in an experimental animal model.


METHODS
Forty rats underwent subcutaneous implantation of a MRSA-colonized arterial polytetrafluoroethylene (PTFE) 1 x 1 cm wafer on the back. The effect of regional antibiosis produced by antibiotic PMMA bead placement adjacent to the infected PTFE wafer was determined using four 10-animal study groups: control (no antibiotic), PMMA bead with no antibiotic, PMMA bead with 10% vancomycin, and PMMA bead with 10% daptomycin. After 3 d, the PTFE wafers were explanted and quantitative biofilm cultures, expressed as colony-forming units (CFU) per graft wafer, performed using real-time polymerase chain reaction to assess MRSA eradication. No systemic antibiotic was administered. Bioassays of antibiotic bead bacteriocidal were performed by measuring zone of inhibition diameters on MRSA colonized agar culture plates prior to and following graft explantation.


RESULTS
All animal tolerated implantation of the MRSA-infected PTFE wafer and survived the 3 d until graft explantation. Quantitative biofilm cultures demonstrated a significant decrease (P < 0.01) in MRSA CFUs present on the PTFE wafer surfaces in the presence of both the vancomycin- and daptomycin-impregnated beads compared to controls and plain PMMA beads. Both vancomycin and daptomycin PMMA beads retained antibacterial activity after 3 d of implantation with decrease in zones of inhibition of 15% and 45%, respectively.


CONCLUSIONS
Regional antibiotic delivery using an antibiotic-impregnated PMMA bead reduced the bacterial biofilm concentration in experimental subcutaneous pocket model of vascular surgical site infection. The delivery of antibiotics via a PMMA bead may be a useful adjunct in the treatment of vascular surgical site infection.
Keeling
W Brent
WB
Division of Vascular and Endovascular Surgery, University of South Florida College of Medicine, Tampa, Florida 33606, USA.
Myers
A Ross
AR
Stone
Patrick A
PA
Heller
Loree
L
Widen
Ray
R
Back
Martin R
MR
Johnson
Brad L
BL
Bandyk
Dennis F
DF
Shames
Murray L
ML
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000627:therapeutic use*; D018441:Biofilms; D017576:Daptomycin / Q000008:administration & dosage / Q000627:therapeutic use; D004195:Disease Models, Animal; D016503:Drug Delivery Systems / Q000379:methods*; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus; D008863:Microspheres; D019904:Polymethyl Methacrylate; D016459:Prosthesis-Related Infections / Q000188:drug therapy* / Q000382:microbiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000382:microbiology; D016896:Treatment Outcome; D014640:Vancomycin / Q000008:administration & dosage / Q000627:therapeutic use
D000900:Anti-Bacterial Agents; D014640:Vancomycin; D019904:Polymethyl Methacrylate; D017576:Daptomycin