HAL will be down for maintenance from Friday, June 10 at 4pm through Monday, June 13 at 9am. More information
Skip to Main content Skip to Navigation
Journal articles

Staphylococcus aureus VRSA-11B Is a Constitutive Vancomycin-Resistant Mutant of Vancomycin-Dependent VRSA-11A

Bruno Périchon 1 Patrice Courvalin 1, *
* Corresponding author
Abstract : 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, IS Ef1 , at the same locus in the vanX-vanY intergenic region of Tn 1546 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 for d -Ala at subsite 1 in Escherichia coli DdlB. VRSA-11B exhibited an additional mutation, P 216 T, in the transcriptional regulator VanR, most probably associated with constitutive expression of vancomycin resistance. It is thus likely that VRSA-11B is a constitutive derivative of VRSA-11A selected during prolonged vancomycin therapy. Synthesis of peptidoglycan precursors ending in d -Ala- d -lactate was responsible for oxacillin susceptibility of VRSA-11A and VRSA-11B despite the presence of a wild-type mecA gene in both strains.
Complete list of metadata

https://hal-pasteur.archives-ouvertes.fr/pasteur-03262725
Contributor : Bruno Perichon Connect in order to contact the contributor
Submitted on : Wednesday, June 16, 2021 - 4:53:14 PM
Last modification on : Thursday, April 7, 2022 - 10:10:29 AM

Links full text

Identifiers

Collections

Citation

Bruno Périchon, Patrice Courvalin. Staphylococcus aureus VRSA-11B Is a Constitutive Vancomycin-Resistant Mutant of Vancomycin-Dependent VRSA-11A. Antimicrobial Agents and Chemotherapy, American Society for Microbiology, 2012, 56 (9), pp.4693-4696. ⟨10.1128/AAC.00454-12⟩. ⟨pasteur-03262725⟩

Share

Metrics

Record views

7