If you need surgery, choose a surgeon with a low infection rate. You should not be afraid to ask your doctor about his infection rate. If your doctor is offended, or won’t tell you, find another surgeon.
You can do much to help yourself, see: Byrne DJ et al., "Rationalizing whole body disinfection," Journal of Hospital Infection 15.2 (1990): 183-187. This study shows that a single shower does not maximize skin disinfection. The authors conclude that three showers should be recommended.
Also see the study by Daryl S. Paulson, "Efficacy Evaluation of a 4% Chlorhexidine Gluconate as a Full-Body Shower Wash," published by the Association for Practitioners in Infection Control (1993). This study found that showering for five days with Chlorhexidine yielded maximum results for reducing bacteria on the skin, and keeping it low for 24 hours or more. "A 1 or 2 day presurgical application period is simply too short to establish the necessary levels of residual antimicrobial properties to be of value.”
So ask your surgeon about his infection rate, and shower with a 4% Chlorhexidine Gluconate soap for five days before going to have elective surgery and stay infection free.