Two Treatments Curbed Surgical Site Infections

Two unrelated preoperative treatments sharply reduced the number of surgical site infections in patients at facilities in the United States and the Netherlands, according to the results of two randomized trials.

In one study, preoperative cleansing of patients' skin with chlorhexidine-alcohol instead of standard povidone-iodine cut the risk of surgical site infection (SSI) by any organism by 41% and the risk of surgical site staph infection by 50%.

In the other study, rapid identification of surgical patients who are nasal carriers of Staphylococcus aureus, followed by immediate treatment with nasal mupirocin ointment, reduced the risk of hospital-acquired S. aureus infections by nearly 60%.

Dr. Rabih O. Darouiche of Baylor College of Medicine,´Houston, and his associates performed what they described as the first prospective, randomized trial that directly compared the efficacy of two skin antiseptics in preventing SSIs.

The study included 813 patients treated at six university-affiliated U.S. hospitals who were undergoing clean-contaminated surgery—colorectal, small intestinal, gastroesophageal, biliary, thoracic, gynecologic, or urologic procedures—performed under controlled conditions without substantial spillage or unusual contamination.

The patients were randomly assigned to undergo either the standard preoperative scrubbing followed by painting with an aqueous solution of 10% povidone-iodine (422 patients) or preoperative scrubbing with applicators containing 2% chlorhexidine gluconate and 70% isopropyl alcohol (391 patients). All subjects also received systemic prophylactic antibiotics preoperatively.

The overall rate of SSI was markedly lower with chlorhexidine (9.5%) than with povidone-iodine (16.1%). The chlorhexidine preparation reduced the rates of both superficial and deep incisional infections, regardless of the type of surgery.

Dr. Darouiche and his colleagues estimated that the number of patients who needed to undergo skin preparation with chlorhexidine-alcohol instead of povidone-iodine in order to prevent one case of SSI was 17.

The proportion of patients infected with an identifiable microorganism was similar between the two groups. There also were no significant differences in the types of microorganisms causing the infections, except that streptococcal infections were less common in patients who received chlorhexidine-alcohol than in those who received povidone-iodine.

The number of adverse events and serious adverse events also was similar between the two groups. Three patients in each group developed pruritus, erythema, or both around the surgical wound, outcomes that were considered to be possibly related to the antiseptic preparations.

“The superior clinical protection provided by chlorhexidine-alcohol is probably related to its more rapid action, persistent activity despite exposure to bodily fluids, and residual effect,” Dr. Darouiche and his associates wrote (N. Engl. J. Med. 2010;362:18–26).

Mupirocin nasal ointment had previously been shown to reduce hospital-associated staph infection, but the authors of the second study said that final proof would be needed from a prospective, randomized clinical trial.

In the study by Dr. Lonneke G.M. Bode of Erasmus University Medical Center, Rotterdam, the Netherlands, and her associates, more than 6,000 surgical patients at three academic and two general hospitals in the Netherlands initially were screened for nasal carriage of S. aureus at hospital admission using a real-time polymerase chain reaction assay. The 917 patients who tested positive were randomly assigned to receive mupirocin nasal ointment plus chlorhexidine gluconate soap for their skin (504 study subjects) or placebo ointment plus placebo soap (413 subjects) before undergoing surgery. The skin treatment was added because nasal carriers of the organism often have both skin and nasal colonization.

The patients, who underwent cardiothoracic, vascular, orthopedic, gastrointestinal, or general procedures, were treated for 5 days regardless of the timing of any interventions, and were followed for staphylococcal SSI for 6 weeks.

A total of 49 patients developed S. aureus infections at the surgical site. The rate was more than twice as high among placebo patients (7.7%) as among those who received active treatment (3.4%).

The treatment benefit was most pronounced in reducing the risk that patients would develop deep SSIs. The rate of such staph infections was 0.9% in patients who received mupirocin vs. 4.4% in those who received placebo.

Mean hospital stay also was significantly reduced—by nearly 2 days—with active treatment, compared with placebo. The only adverse effect of active treatment was local irritation, which resolved after mupirocin treatment was discontinued.

“The results of our trial provide solid evidence of the preventive effect of S. aureus decolonization and a good estimate of the size of this effect: The risk of hospital-associated S. aureus infections was reduced by nearly 60%,” Dr. Bode and her colleagues wrote (N. Engl. J. Med. 2010;362:9–17´. “It is plausible that this strategy would also be effective in carriers of methicillin-resistant strains of S. aureus that are susceptible to mupirocin.”