Antibiotic Ointment Might Reduce Risk Of Dangerous Staph Infections

Ruzanna Harutyunyan's picture
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A nasal antibiotic ointment could slash rates of staph infection without causing antibiotic resistance, a new review of studies concludes.

Physicians should consider the use of intranasal mupirocin to reduce the infection rate in hospitalized patients who test positive as nasal carriers of the Staphylococcus aureus bacteria, said Miranda van Rijen, the lead review author.

Up to 30 percent of people are nasal carriers of staph aureus, which simply means they carry the bacteria in their nostrils but it does not cause an infection. Most of the time, staph causes no infection or involves only minor skin problems. However, it can sometimes lead to serious complications.

Mupirocin (also known by its brand name, Bactroban, which GlaxoSmithKline manufactures) is a topical antibiotic that is effective against several bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). The drug works by blocking the activity of an enzyme within bacteria.

The U.S. Food and Drug Administration approved the intranasal form of the drug in 1995.

Led by van Rijen, an infection control practitioner at Amphia Hospital Breda in the Netherlands, researchers reviewed nine randomized controlled trials involving 3,396 patients who were nasal carriers of staph aureus.

The studies took place in Europe, Canada, Colombia and the United States.

The review appears in the latest issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.

Researchers found that patients who received intranasal mupirocin had about half the rates of staph infection after treatment, compared to patients who received no treatment or a placebo.

Staph infections can cause significant complications in hospitalized patients: pneumonia, surgical wound infections, urinary tract infections and blood-borne bacterial infections.

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The findings of this review are not applicable to all hospital patients, the authors said. They only apply to patients who are nasal carriers; previous studies showed that mupirocin was not effective in reducing staph infections when applied to all patients.

"We were not surprised by the results," van Rijen said. "In our hospital, mupirocin has been used routinely in cardiothoracic surgery for several years and our S. aureus infection rate is very low."

What is surprising, though, are the relatively few trials investigating this interesting strategy, considering the current pandemic of staph infections in hospitals.

Until now, "routine use of mupirocin has not been applied in many hospitals, mainly due to concern about the development of mupirocin resistance and the absence of convincing evidence that mupirocin reduces the infection rate," van Rijen said.

In the past, using mupirocin for prolonged periods, especially as a skin ointment, resulted in antibiotic resistance. But the authors found that short-term use — a five-day course of treatment — did not seem to be associated with antibiotic resistance.

That might be true on an individual patient basis, but fails to address the big picture of antibiotic resistance, a U.S. expert argues.

"If the 'short-term use' meant five days of therapy for every patient in a hospital — or even every surgical patient in a hospital where the average stay was three days — then a large portion of the constantly changing inpatient population would be on mupirocin therapy," said Barry Farr, M.D., professor emeritus of medicine and epidemiology at the University of Virginia.

If the hospital happened to admit a patient colonized with a mupirocin-resistant strain, this scenario might foster spread of the resistant strain, Farr said.

In general, the conclusion is likely correct that mupirocin can significantly reduce staph infections among colonized patients, Farr said. However, he added, "some important things can be and often are learned about a drug after it is marketed, outside the confines of randomized trials."

The review finds no important adverse effects in the randomized studies, but does not mention observations outside of randomized studies. For example, a Swiss patient reportedly developed a fatal toxic skin disorder at a site on the nose following mupirocin application, making it appear that rare severe adverse effects from mupirocin could occur, Farr said. That single case was reported in the June 2003 issue of the journal Infection Control and Hospital Epidemiology.

The review discloses that review co-author Marc Bonten has received funding from 3M.

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