Table 5.
Mechanisms of reduced vancomycin susceptibility or vancomycin resistance among various strains of Enterococcus and Staphylococcus species
| Organisms | Mechanism of reduced vancomycin susceptibility |
|---|---|
| Enterococci | By acquisition of following genotypes: VanA/VanB/VanC/VanD/VanE |
| Staphylococci Fully resistant strains Strains with reduced vancomycin susceptibility
|
By acquisition of VanA gene from vancomycin resistant enterococci (VRE) By having mutations in either graRS/vraSR/walKR operon leading ultimately to cell wall thickening, decreased autolysis, reduced protein A production, increased capsule expression, increased D-alanylation of teichoic acid, and reduced accessory gene regulator (agr) activity. These are the vancomycin susceptible Staphylococcus aureus strains which upon subculture produce subcolonies with vancomycin resistance |