A multi-center study led by infection control experts with University of Iowa Health Care finds that implementing a series of simple interventions before surgery can reduce the rate of surgical-site infections (SSIs) by up to 40 percent.

The study, published in the June 2 issue of JAMA, tested the effectiveness of a "bundle" of evidence-based interventions for lowering SSIs caused by Staphylococcus aureus (staph) bacteria in patients undergoing heart surgery or hip or knee replacement procedures.

The interventions included screening patients for the presence of staph bacteria in their noses; having patients who tested positive apply an antibiotic ointment in their noses and bathe with an antimicrobial wash for up to five days before the surgery; and giving all patients appropriately targeted antibiotics just before surgery—patients who tested positive for methicillin-resistant S. aureus (MRSA) received vancomycin and cefazolin or cefuroxime, while all other patients received cefazolin or cefuroxime only.

Approximately one in three people have staph bacteria inside their noses. This colonization is generally harmless, but if these bacteria get into a surgical incision they can cause a severe infection, which can have serious health and financial consequences. In addition to causing potentially life-threatening health complications, an SSI can add between $13,000 to $100,000 to the cost of health care.

Twenty hospitals in nine U.S. states participated in the study and rates of SSIs were collected for a median of 39 months during the pre-intervention period and a median of 21 months during the intervention period.

Overall, 101 complex staph SSIs occurred after 28,218 operations during the pre-intervention period and 29 occurred after 14,316 operations during the intervention period. The rates of complex staph SSIs decreased for hip or knee replacement by 17 for every 10,000 operations, and by six for every 10,000 heart operations.

"Patients undergoing total hip or knee replacements and cardiac operations should be tested to see if they carry the staph bacteria in their noses. If they do carry the staph bacteria, the protocol we describe in the paper can lower their risk of a serious staph infection by about 40 percent," says Loreen Herwaldt, UI professor of internal medicine, director of hospital epidemiology at UI Hospitals and Clinics, and senior author on the study.

The intervention strategy was developed by the UI physicians based on a review, or meta-analysis, of 39 studies of various surgical-site infection practices employed at hospitals nationwide. This new study tested the effectiveness of the bundled intervention by implementing it systematically in a multi-center study. The significant effect on SSI rates was found despite the fact that a number of factors could have lowered the likelihood that the researchers would observe a strong effect.

"We did this study in a hospital system that already had low rates of serious S. aureus SSIs and that had already implemented parts of the bundle. In addition, we did it under real-life conditions rather than the best case conditions of a randomized clinical trial, and we included patients getting urgent or emergency surgeries who would not normally be included in a randomized clinical trial," Herwaldt explains. "All these factors were biasing us away from finding a significant decrease—but we did find one."

After a three-month phase-in period, full adherence to the bundle of interventions was 39 percent and partial adherence was 44 percent. For patients who followed the protocol completely, there was a significant decrease in the rate of SSI caused by staph compared with the pre-intervention period. However, SSI rates did not decrease significantly for patients who did not follow the protocol or only partially followed it.

This project was funded by the Agency for Healthcare Research and Quality of the U.S. Department of Health and Human Services. It also received support from VA Health Services Research and Development. 

In addition to Herwaldt, UI researchers on the team included Marin Schweizer, Hsiu-Yin Chiang, Melissa Ward, Joseph Cavanaugh, Eli Perencevich, and Daniel Diekema. Schweizer and Perencevich also have appointments with the Iowa City VA Health Care System; Edward Septimus, Julie Moody, Jason Hickok, and Jonathan Perlin are at Hospital Corporation of America in Nashville, Tennessee; and Barbara Braun, Joanne Hafner, and Cheryl Richards, of the Joint Commission in Oakbrook Terrace, Illinois, were also part of the research team.

(Note to Editors: This release contains information from a news release issued by JAMA media relations staff.)