Penile prosthesis infection risk reduced with solution

March 1, 2011

In vitro studies suggest that a solution of rifampin and gentamicin applied to the Titan inflatable penile prosthesis as part of a rigorous infection control protocol can significantly reduce the risks of infection by Staphylococcus epidermidis and Escherichia coli acquired during the implant procedure.

Key Points

Chirpriya Dhabuwala, MD, chief of urology at the Harper University Hospital and Hutzel Women's Hospital in Detroit, presented in vitro data on the proprietary solution at the 2010 AUA annual meeting in San Francisco.

Dr. Dhabuwala noted that since he implemented a protocol employing the solutions 5 years ago, he has implanted prostheses in 85 or more patients and has yet to see an infection.

Dr. Dhabuwala said that he now employs two rifampin-gentamicin solutions during implant procedures. He irrigates the surgical bed with a solution of rifampin, 1 mg/mL, plus gentamicin, 1 mg/mL (R1/G1 solution) throughout the procedure and then, using a syringe, he coats the surface of the implant with a rifampin, 10 mg/mL, plus gentamicin, 1 mg/mL solution (R10/G1 solution).

The solutions Dr. Dhabuwala now uses were the result of a series of tests designed to identify the combination of antimicrobials that would provide the greatest protection against S. epidermidis and E. coli infection. He tested six different solutions against a saline control and against strips of InhibiZone (American Medical Systems, Minnetonka, MN), the antibiotic impregnating the surface of AMS penile implants. The solutions included varied concentrations of rifampin alone, rifampin plus gentamicin, rifampin plus gentamicin plus vancomycin, and bacitracin plus gentamicin. These were coated on strips of the Titan implant material and subjected to zone of inhibition studies.

Dr. Dhabuwala and colleagues found that two rifampin-based solutions (R1/G1 and R10/G1) produced the strongest bactericidal effects. Their zones of inhibition appeared to be 40% to 56% greater than those produced by InhibiZone-coated strips.

The zone of inhibition tests showed that compared to all the other antibiotics, rifampin offered the best protection against S. epidermidis.

The solutions are now incorporated into a rigid protocol designed to diminish eliminate the smallest risk of infection. That protocol begins with urine cultures obtained 3 weeks before surgery. Any bacterial growth is treated with the appropriate antibiotics up to the day of the surgery and 2 weeks afterwards.

The patient is given presurgical antibiotic prophylaxis with intravenous cephalosporin and gentamicin about 1 hour prior to surgery. The surgical area is shaved in the preoperative surgical area within 2 hours before surgery, and is done with a razor, not clippers. The area is thoroughly scrubbed with povidone-iodine for 15 minutes in the operating room and painted with povidone-iodine paint. All involved personnel are required to scrub their hands and forearms for 15 minutes before double gloving, and traffic in the operating room is kept to an absolute minimum.

Laminar flow is initiated in the operating room throughout the procedure. Patients receive oral ciprofloxacin (Cipro, Proquin XR), 500 mg twice daily for 14 days following the procedure.

Dr. Dhabuwala and colleagues have completed a clinical study of the protocol, the solutions, and clinical outcomes, and the data were published online in the Journal of Sexual Medicine (Oct. 12, 2010).

Dr. Dhabuwala receives research support from and is a consultant to Coloplast.