Multiply-Resistant Enterococcus faecium

Abstract

IN THE PAST 10 years, the microbiology of nosocomial infections has changed considerably. Hospital-acquired infections due to enteric gram-negative bacilli have decreased in incidence, while those due to gram-positive organisms and fungi have increased. Between 1986 and 1989, enterococci comprised 12% of nosocomial infections, second only to<i>Escherichia coli</i>in incidence.¹ Enterococci are less susceptible to penicillin than are related streptococci. This difference is thought to be due to the production of penicillin-binding proteins that have lower affinities for penicillin than do those of streptococci.²Recently, β-lactamase—producing enterococci have also been described as important nosocomial pathogens.^3,4 Enterococci are intrinsically resistant to clinically useful levels of aminoglycosides. However, when used in conjunction with penicillins, synergistic bactericidal activity has been demonstrated in vitro. In the past two decades, high-level aminoglycoside resistance, first to streptomycin and later to gentamicin, has occurred with increasing frequency. From 1981 to 1989, the incidence