Vancomycin Resistance in Gram-Positive Cocci

The first vancomycin-resistant clinical isolates of Enterococcus species were reported in Europe in 1988. Similar strains were later detected in hospitals on the East Coast of the United States. Since then, vancomycin-resistant enterococci have spread with unexpected rapidity and are now encountered in hospitals in most countries. This article reviews the mode of action and the mechanism of bacterial resistance to glycopeptides, as exemplified by the VanA type, which is mediated by transposon Tn1546 and is widely spread in enterococci. The diversity, regulation, evolution, and recent dissemination of methicillin-resistant Staphylococcus aureus are then discussed.