A new study in the New England Journal of Medicine reports that use of mupirocin nasal ointment (Bactroban Nasal [mupirocin calcium]) in the noses of patients before surgery significantly reduces the rate of Staphylococcus aureus (S. aureus) nosocomial (hospital-acquired) infections among patients who are carriers of this bacteria.

The study conducted at the University of Iowa Hospitals and Clinics evaluated the efficacy of mupirocin nasal ointment as compared to placebo in patients undergoing general, neurosurgical or cardiothoracic operations.

Staphylococcus aureus is a common cause of postoperative infections. This type of bacteria is carried in the nose of 25-30 percent of healthy individuals. Patients who are carriers of the bacteria are at higher risk of acquiring S. aureus infections after invasive medical or surgical procedures than individuals who do not carry the organism.

"The study is the first large, well-controlled, double-blinded trial in surgical patients to show that mupirocin nasal ointment had a protective effect in people who are nasal carriers of S. aureus," said Pamela P. French, M.D., M.P.H., co-author for the study. "This is an important finding because while the incidence of postoperative infection may be relatively low, the impact of S. aureus infections in people recovering from major surgery can be catastrophic."

The double-blind, placebo-controlled study evaluated 3,864 adults undergoing general, gynecologic, cardiothoracic and neurosurgical operations. Study medication or placebo was applied to the interior of the nose twice daily for up to five days prior to surgery. In addition, surgeons followed standard clinical practices and used standard prophylactic antimicrobial regimens.

The study evaluated the effect of treatment on patients regardless of whether they carried S. aureus and separately examined the results among the subgroup of individuals known to carry the organism. Study results showed that mupirocin nasal ointment presurgical treatment significantly cut down the rate of postoperative S. aureus nosocomial infections in patients who were S. aureus nasal carriers.

S. aureus carriage was eliminated in 83.4 percent of the mupirocin-treated group versus 27.4 percent of placebo-treated patients.

Mupirocin nasal ointment significantly decreased the rate of S. aureus nosocomial infections among nasal carriers, the group expected to be at risk.

S. aureus surgical site infections were reduced by almost 50 percent among people who were S. aureus carriers who received mupirocin nasal ointment before cardiothoracic or general surgery procedures versus a similar group of placebo treated individuals.

The rates of side effects with mupirocin nasal ointment in the study were low and similar to placebo (4.8 percent reported per study group). The most commonly reported side effects in both groups were rhinorrhea (runny nose) and itching at the application site.

It was also determined through microbial testing that a single short course of mupirocin nasal ointment for preoperative prophylaxis did not appear to lead to the development of drug resistance.

The study authors conclude, "Mupirocin therapy is safe, has a protective effect among nasal carriers of S. aureus, and is a reasonable adjuvant agent to prevent such infections in carriers after surgery."

This study was supported by a research grant from GlaxoSmithKline. Mupirocin nasal ointment (Bactroban Nasal) is a topical antibiotic that is designed for use in the nose. Bactroban(r) Nasal (mupirocin ointment) 2% is indicated for the eradication of nasal carriage in healthcare workers and adult patients at high risk of methicillin-resistant S. aureus infection during institutional outbreaks of this pathogen. The most commonly reported adverse events were headache (9%) and rhinitis (6%).