Staphylococcus epidermidis: An Increasing Cause of Infection in Patients with Granulocytopenia

Abstract

S. epidermidis, a major component of the skin flora, is usually considered a contaminant when recovered from diagnostic cultures. Since 1974 infections caused by gram-negative bacilli and S. aureus occurring among patients with granulocytopenic cancer have remained constant; infections due to S. epidermidis occurring before 1977 at a rate of 2.0/1000 days of hospitalization of patients with acute leukemia, increased to 14.6/1000 days in 1979. All S. epidermidis infections before 1977 originated from skin sites; since 1977 the respiratory tract and alimentary canal have become the predominant sites of origin. Predisposing factors for infection were profound granulocytopenia (< 100/.mu.l), a diagnosis of acute leukemia and an oral nonabsorbable antibiotic regimen lacking vancomycin. The increased incidence of infection was not related to a nosocomial source or the more frequent use of long-term indwelling catheters. Methicillin resistance among isolates was common (40%). Vancomycin (i.v.) therapy provided the best therapeutic results. Diagnostic cultures positive for S. epidermidis in the setting of infection and profound granulocytopenia warrant appropriate antibiotic therapy.