Rapid Dissemination of β-Lactamase–Producing, Aminoglycoside-ResistantEnterococcus faecalisamong Patients and Staff on an Infant–Toddler Surgical Ward

Abstract

ALTHOUGH enterococci are normal inhabitants of the gastrointestinal and female genital tracts, they are now recognized as formidable pathogens in hospitalized patients.^{1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17} Many patients become infected with their own strains of enterococci after they are admitted to the hospital,¹⁸ but nosocomial transmission occurs as well.^{19 , 20} Recently, strains of enterococci with high-level resistance (>500 to >2000 μg per milliliter) to gentamicin and other aminoglycosides have been detected in hospitals around the world,^{8 , 9 , 19 20 21 22 23} reaching epidemic proportions in some institutions. Bactericidal synergism with penicillins or vancomycin is not observed with these strains, considerably complicating therapy. A few isolated aminoglycoside-resistant strains of Enterococcus faecalis (Streptococcus faecalis) have been reported that also produce β-lactamases,^{24 , 25} further narrowing the therapeutic options. In this report we describe the rapid spread of a multiply resistant strain of E. faecalis on an infant–toddler surgical ward and identify the risk factors for nosocomial colonization; our observations include the surprising finding that a nurse who carried the organism in her gastrointestinal tract and on her hands was involved in sustaining the outbreak.