ABSTRACT
Introduction Enterococci are part of the normal microbial flora of the human intestinal tract. They were regarded for a long time as minor opportunistic pathogens causing occasional cases of endocarditis or urinary tract infection (UTI). However, since the late 1980s enterococci have been increasingly recognized as important nosocomial pathogens, affecting particularly cancer patients who are neutropenic or have underlying haematological malignancies, patients in intensive care units (ICUs) or renal units, and recipients of transplanted organs. Moreover, the treatment of enterococcal infections is often problematic because of the intrinsic resistance of enterococci to cephalosporins, low levels of other ~-lactams and aminoglycosides, and their welldocumented ability to develop resistance to most other classes of antimicrobial agents, including glycopeptides, often by acquisition of genes encoding resistance. Recently the ability of enterococci to exchange genetic material has achieved new prominence with the finding that genes encoding resistance to vancomycin appear to have passed from vancomycin-resistant enterococci (VRE) to Staphylococcus aureus, resulting in clinical isolates of the latter species with high-level resistance 11-31.
