title: In vivo efficacy of antimicrobe-impregnated saline-filled silicone implants.
abstract: Bacterial colonization of mammary implants is a prelude to clinical infection and has been implicated in the etiology of capsular contracture. Antimicrobial impregnation of a variety of medical devices with the combination of minocycline and rifampin has recently emerged as a potentially effective method for preventing device colonization and device-related infection. The objective of this animal study was to examine in vivo the antimicrobial efficacy of minocycline/rifampin-impregnated, saline-filled silicone implants. A rabbit model of Staphylococcus aureus colonization and infection of subcutaneously placed implants was used. A total of 48 saline-filled silicone implants (24 antimicrobe-impregnated and 24 control unimpregnated implants) were suspended in a 106 colony-forming units/ml bacterial suspension of S. aureus for 30 minutes at room temperature, allowed to dry for 60 minutes, and then implanted subcutaneously in the back of 12 rabbits (two antimicrobe-impregnated and two control implants were placed in each rabbit). Rabbits were monitored daily, then killed either at 2 weeks (10 rabbits) or at 4 weeks (two rabbits) and cultured. The antimicrobe-impregnated implants were 12 times less likely to be colonized than control unimpregnated implants (two of 24 versus 23 of 24; p < 0.001), and they were a significantly less likely cause of implant-related infection (0 of 24 versus 22 of 24; p < 0.001) and implant-related abscess (0 of 24 versus 21 of 24; p < 0.001) than control implants. The minocycline/rifampin-impregnated implants routinely demonstrated zones of inhibition against S. aureus at the time of explantation. These results indicate that minocycline/rifampin-impregnated implants can significantly decrease the rate of bacterial colonization, implant-related infection, and implant-related abscess. Antimicrobe-impregnated implants also have the potential of reducing the likelihood of capsular contracture.
authors.affiliation: Center for Prostheses Infection, Infectious Disease Section, and Division of Plastic Surgery, Veterans Affairs Medical Center and Baylor College of Medicine, Houston, Texas 77030, USA. rdarouiche@aol.com
authors.forename: Rabih O
authors.initials: RO
authors.lastname: Darouiche
authors.forename: Ricardo
authors.initials: R
authors.lastname: Meade
authors.forename: Mohammad D
authors.initials: MD
authors.lastname: Mansouri
authors.forename: David T
authors.initials: DT
authors.lastname: Netscher
mesh_terms: D000818:Animals; D018427:Breast Implants; D005260:Female; D008911:Minocycline / Q000008:administration & dosage*; D016459:Prosthesis-Related Infections / Q000517:prevention & control*; D011817:Rabbits; D012293:Rifampin / Q000008:administration & dosage*; D012828:Silicones; D013047:Specific Pathogen-Free Organisms; D013203:Staphylococcal Infections / Q000517:prevention & control
chemical_list: D012828:Silicones; D008911:Minocycline; D012293:Rifampin