In vivo efficacy of antimicrobial-coated fabric from prosthetic heart valve sewing rings.
OBJECTIVE
Antimicrobial coating of medical devices has recently emerged as a potentially effective method for preventing device-related infections. The objective of this animal study was to examine in vivo the antimicrobial efficacy of prosthetic heart valve sewing ring fabric coated with: (i) silver; (ii) combined minocycline and rifampin (M/R); or (iii) combined chlorhexidine and chloroxylenol (CH/CX).


METHODS
A rabbit model of Staphylococcus aureus colonization and infection of subcutaneously implanted fabric of prosthetic heart valve sewing rings was used. Following administration of anesthesia and preoperative antibiotic prophylaxis, 0.5 x 0.5 cm samples of fabric were placed subcutaneously into the back of rabbits. Each rabbit received a total of eight samples: (i) two uncoated; (ii) two silver-coated; (iii) two M/R-coated; and (iv) two CH/CX-coated. After injecting a bacterial inoculum of 2 x 10(5) c.f.u. of S. aureus onto each implanted sample, the wounds were sutured. Rabbits were monitored daily for one week, killed and the test fabrics removed and cultured.


RESULTS
Rates of device colonization, device-related infection and device-related abscess were similar between the uncoated and silver-coated devices. Devices coated with M/R were less likely to be colonized or cause device-related infection when compared with uncoated devices, and less likely to be associated with abscess formation than silver-coated devices. There was a tendency for CH/CX-coated devices to be less colonized than uncoated devices. Only M/R-coated and CH/CX-coated devices produced zones of inhibition in vitro. Implantation of M/R-coated and CH/CX-coated devices in rabbits did not result in detectable systemic concentrations of the antimicrobial coating agents. Colonization of antimicrobial-coated devices was not associated with resistant S. aureus isolates.


CONCLUSIONS
These results suggest that silver-coated sewing rings may not prove to be clinically anti-infective. In contrast, antimicrobial-coated sewing rings that produce effective zones of inhibition, particularly those coated with M/R, are likely to be clinically protective.
Darouiche
R O
RO
Department of Medicine, Baylor College of Medicine, Houston, Texas, USA.
Meade
R
R
Mansouri
M
M
Raad
I I
II
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage* / Q000627:therapeutic use; D019072:Antibiotic Prophylaxis; D001422:Bacterial Adhesion / Q000187:drug effects; D002710:Chlorhexidine / Q000008:administration & dosage / Q000627:therapeutic use; D020099:Coated Materials, Biocompatible; D015169:Colony Count, Microbial; D004195:Disease Models, Animal; D004338:Drug Combinations; D005260:Female; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D008911:Minocycline / Q000008:administration & dosage / Q000627:therapeutic use; D011474:Prosthesis Design; D016459:Prosthesis-Related Infections / Q000517:prevention & control*; D011817:Rabbits; D012293:Rifampin / Q000008:administration & dosage / Q000627:therapeutic use; D012837:Silver Sulfadiazine / Q000008:administration & dosage / Q000627:therapeutic use; D013203:Staphylococcal Infections / Q000517:prevention & control
D000900:Anti-Bacterial Agents; D000891:Anti-Infective Agents, Local; D020099:Coated Materials, Biocompatible; D004338:Drug Combinations; D008911:Minocycline; D002710:Chlorhexidine; D012293:Rifampin; D012837:Silver Sulfadiazine