Intrinsic and acquired resistance mechanisms in enterococcus

Abstract

Enterococci have the potential for resistance to virtually all clinically useful antibiotics. Their emergence as important nosocomial pathogens has coincided with increased expression of antimicrobial resistance by members of the genus. The mechanisms underlying antibiotic resistance in enterococci may be intrinsic to the species or acquired through mutation of intrinsic genes or horizontal exchange of genetic material encoding resistance determinants. This paper reviews the antibiotic resistance mechanisms in Enterococcus faecium and Enterococcus faecalis and discusses treatment options.

Figure 1. An illustration of the VanA resistance mechanism as it relates to normal cell wall synthesis. The top pathway denotes normal cell wall synthesis, and the mechanisms by which VanX and VanY disrupt this pathway. The shaded pathway denotes construction of a modified cell wall that is resistant to vancomycin. Adapted from Gold et al.