Objectives: To assess, in an animal study, the efficacy of minocycline/rifampin-impregnated silicone sections of pump bulbs from penile implants in preventing device colonization by Staphylococcus aureus. Infection constitutes a very serious complication of penile implants.
Methods: Minocycline/rifampin-impregnated and control silicone pump bulb sections from penile implants were each inoculated with about 10(3) to 10(4) colony-forming units of S. aureus. After 8 hours of incubation with bacteria at room temperature, the test devices were allowed to dry for 30 minutes, and then subcutaneously implanted in the backs of rabbits. Eleven rabbits each received a total of six devices. The wounds were sutured, and the rabbits were monitored daily, then killed at 2 days after surgery. In vitro zones of inhibition against S. aureus by the minocycline/rifampin-impregnated and control devices were also determined.
Results: All of the six tested antimicrobial-impregnated devices but none of the control devices produced zones of inhibition in vitro against S. aureus (mean zone of inhibition by antimicrobial-impregnated devices of 23 mm). The antimicrobial-impregnated devices retrieved from rabbits were sixfold less likely than were the control devices to be colonized with S. aureus (2 [6%] of 33 versus 11 [33%] of 33, respectively; P = 0.011).
Conclusions: The results of this animal study indicate that minocycline/rifampin-impregnated pump bulb sections from penile implants provide antimicrobial activity in vitro against S. aureus and protect against staphylococcal colonization of devices implanted for 2 days in animals.