[Hospital personnel who are nasal carriers of methicillin-resistant Staphylococcus aureus. Usefulness of treatment with mupirocin].

BACKGROUND: The evaluation of health care workers role in methicillin-resistant Staphylococcus aureus outbreaks and the efficacy of mupirocin as a topical agent for nasal carriers.
METHOD: Microbiologic study of nasal microflora of 1547 health care workers from the San Carlos University Hospital and 108 health care workers from related hospitals while an outbreak of methicillin-resistant Staphylococcus aureus nosocomial infections is in progress at San Carlos University Hospital. Assessment of the efficacy of mupirocin nasal ointment for nasal carriers using microbiologic controls of nasal and pharyngeal swabs at the end of treatment and two weeks after.
RESULTS: In San Carlos University Hospital a total of 53 health care workers with nasal carriage of methicillin-resistant Staphylococcus aureus were found. That figure represents a 3.4% of all health care workers studied and also a 15.4% of methicillin-resistance among all S. aureus isolated. Among health care workers from related hospitals, only one nasal carrier was found. Forty-seven of all 53 methicillin-resistant Staphylococcus aureus isolated from San Carlos University Hospital health care workers and the strain isolated from the related hospitals health care worker were similar to the epidemic strain responsible for the outbreak. Mupirocin, as nasal ointment, was useful in eliminating nasal colonization in all cases.
CONCLUSIONS: When a nosocomial outbreak of methicillin-resistant Staphylococcus aureus infections is detected, health care workers are one of the most important reservoirs. Topical treatment with mupirocin (nasal ointment) is useful for eliminating the nasal carrier status.