Effects of Antibiotic Nose Ointment for Hospitalized Patients with Staphylococcus aureus

Summaries for Patients are a service provided by Annals to help patients better understand the complicated and often mystifying language of modern medicine.

Summaries for Patients are presented for informational purposes only. These summaries are not a substitute for advice from your own medical provider. If you have questions about this material, or need medical advice about your own health or situation, please contact your physician. The summaries may be reproduced for not-for-profit educational purposes only. Any other uses must be approved by the American College of Physicians.

The summary below is from the full report titled "Mupirocin Prophylaxis against Nosocomial Staphylococcus aureus Infections in Nonsurgical Patients. A Randomized Study." It is in the 16 March 2004 issue of Annals of Internal Medicine (volume 140, pages 419-425). The authors are H.F.L. Wertheim, M.C. Vos, A. Ott, A. Voss, J.A.J.W. Kluytmans, C.M.J.E. Vandenbroucke-Grauls, M.H.M. Meester, P.H.J. van Keulen, and H.A. Verbrugh.

What is the problem and what is known about it so far?

Staphylococcus aureus (S. aureus) is a common bacteria. Many healthy people have it on their skin or in their noses. Occasionally it causes infections. Most are minor skin infections, such as pimples and boils. However, S. aureus can cause serious infections, such as pneumonia, septicemia (bloodstream infection), and wound infections. The serious infections most often occur in people with depressed immune systems, recent surgery, long-term dialysis, or recent hospitalization for a major illness. People in these situations have increased risks for the serious S. aureus infections if they have S. aureus in their noses. Doctors know that rubbing antibiotic ointment inside the nose helps rid it of S. aureus bacteria. But they don't know whether giving the antibiotic nose ointment actually prevents serious S. aureus infections.

Why did the researchers do this particular study?

To find out whether mupirocin ointment is better than placebo ointment in preventing infections in hospitalized patients who have S. aureus in their noses.

Who was studied?

1602 patients with S. aureus in their noses who were hospitalized in nonsurgical departments of 4 hospitals.

How was the study done?

Nurses swabbed patients' nares at admission and sent the swabs for culture. The researchers randomly assigned the patients with positive cultures for S. aureus to receive either mupirocin ointment or placebo ointment. Ointments were applied inside both nares (intranasally) twice a day for 5 days. The researchers and the patients did not know who got which ointment. The researchers checked the cultures at the hospital laboratories weekly until 6 weeks after each patient's discharge. If they found a positive culture, the researchers reviewed medical records and sometimes talked to the patients' doctors to figure out the type of infection that the patient had had. The researchers then compared rates of S. aureus infections among patients who had and had not received the mupirocin ointment.

What did the researchers find?

Staphylococcus aureus infection rates were similar whether patients received mupirocin (2.6%) or placebo (2.8%) ointment. Two patients in each group reported that the ointment burned or caused itching.

What were the limitations of the study?

Few patients got infections, which limited the researchers' ability to rule out small but potentially important differences in infection rates among people given mupirocin and placebo ointment. Patients with positive nasal cultures were given mupirocin 1 to 3 days after admission. Giving mupirocin earlier might have had a different effect.

What are the implications of the study?

Applying intranasal mupirocin ointment to patients who carry S. aureus in their nose did not prevent S. aureus infections in hospitalized, nonsurgical patients.