Staphylococcus aureus VRSA-11B is a constitutive vancomycin-resistant mutant of vancomycin-dependent VRSA-11A.

ABSTRACT: Vancomycin-resistant Staphylococcus aureus VRSA-10 was isolated in 2009, whereas VRSA-11A and VRSA-11B were isolated from the same patient in 2010. Growth curves and determination of the nature of the peptidoglycan precursors and of the VanX d,d-dipeptidase activity in the absence and in the presence of vancomycin indicated that vancomycin resistance was inducible in VRSA-10, that VRSA-11A was partially dependent on glycopeptide for growth, and that VRSA-11B was constitutively resistant. Both VRSA-11A and -11B harbored an insertion sequence, ISEf1, at the same locus in the vanX-vanY intergenic region of Tn1546 and an S(183)A mutation in the chromosomal d-alanyl:d-alanine ligase (Ddl). This substitution has been shown to be responsible for a drastic diminution of the affinity of the enzyme

SUBMITTER: Perichon B 

PROVIDER: S-EPMC3421854 | biostudies-literature | 2012 Sep

REPOSITORIES: biostudies-literature