Most of the characteristics that have ensured the success of enterococ
ci as nosocomial pathogens were described early in this century. Enter
ococcus faecium and Enterococcus faecalis, the enterococci most freque
ntly isolated from clinical material, differ fundamentally, The intrin
sic antimicrobial resistance of Enterococcus faecium, supplemented by
acquired resistance mechanisms, can generate a glycopeptide-multiply-r
esistant nosocomial pathogen that survives on hands and in the environ
ment, and has the potential for intra-hospital and inter-hospital spre
ad. The use of terms such as 'an enterococcus', 'faecal streptococci'
and 'group D streptococci' have hindered, and still hinder, our unders
tanding of a species rapidly emerging as the most problematic of nosoc
omial pathogens.