Table 1.

Phenotype associated with alterations of VanS and VanSB functions in E. faecalis

Function alteration and allele (cluster)Expression of resistance genes
None
 Wild-type vanS(vanA)Inducible by VAN, TEC, and MOEa
 Wild-typevanSB (vanB)Inducible by VAN
Loss of all functions
 Null allele of vanS (vanA) Constitutive (inducible by VAN, TEC, and MOE ifPH titrates phospho-VanR)
 Null allele ofvanSB (vanB) Clonal variation, inducible by VAN, TEC, and MOE
Loss of kinase activity due to substitutions at autophosphorylation site
vanS H164Q (vanA)Repressed under all conditions
vanSB H233Q (vanB)Inducible by VAN
Alteration of signal recognition or transduction due to substitution in sensing domainb
vanSB A30G (vanB)Inducible by VAN and TEC
vanSB D168Y (vanB)Inducible by VAN and TEC
Impaired phosphatase activity due to substitutions in H box
vanSB S232Y (vanB)Constitutive
vanSB Y237M or K (vanB)Constitutive
  • a MOE, moenomycin; TEC, teicoplanin; VAN, vancomycin.

  • b The substitutions were located in the external loop (e.g., A30G) or in the linker (e.g., D168Y) of VanSB.