Titre
Vancomycin-intermediate Staphylococcus aureus selected during vancomycin therapy of experimental endocarditis are not detected by culture-based diagnostic procedures and persist after treatment arrest.
Type
article
Institution
UNIL/CHUV/Unisanté + institutions partenaires
Périodique
Auteur(s)
Moreillon, P.
Auteure/Auteur
Bizzini, A.
Auteure/Auteur
Giddey, M.
Auteure/Auteur
Vouillamoz, J.
Auteure/Auteur
Entenza, J.M.
Auteure/Auteur
Liens vers les personnes
Liens vers les unités
ISSN
1460-2091
Statut éditorial
Publié
Date de publication
2012
Volume
67
Numéro
3
Première page
652
Dernière page/numéro d’article
660
Langue
anglais
Résumé
OBJECTIVES: Laboratory detection of vancomycin-intermediate Staphylococcus aureus (VISA) and their heterogeneous VISA (hVISA) precursors is difficult. Thus, it is possible that vancomycin failures against supposedly vancomycin-susceptible S. aureus are due to undiagnosed VISA or hVISA. We tested this hypothesis in experimental endocarditis.¦METHODS: Rats with aortic valve infection due to the vancomycin-susceptible (MIC 2 mg/L), methicillin-resistant S. aureus M1V2 were treated for 2 days with doses of vancomycin that mimicked the pharmacokinetics seen in humans following intravenous administration of 1 g of the drug every 12 h. Half of the treated animals were killed 8 h after treatment arrest and half 3 days thereafter. Population analyses were done directly on vegetation homogenates or after one subculture in drug-free medium to mimic standard diagnostic procedures.¦RESULTS: Vancomycin cured 14 of 26 animals (54%; P<0.05 versus controls) after 2 days of treatment. When vegetation homogenates were plated directly on vancomycin-containing plates, 6 of 13 rats killed 8 h after treatment arrest had positive cultures, 1 of which harboured hVISA. Likewise, 6 of 13 rats killed 3 days thereafter had positive valve cultures, 5 of which harboured hVISA. However, one subculture of vegetations in drug-free broth was enough to revert all the hVISA phenotypes to the susceptible pattern of the parent. Thus, vancomycin selected for hVISA during therapy of experimental endocarditis due to vancomycin-susceptible S. aureus. These hVISA were associated with vancomycin failure. The hVISA phenotype persisted in vivo, even after vancomycin arrest, but was missed in vitro after a single passage of the vegetation homogenate on drug-free medium.¦CONCLUSIONS: hVISA might escape detection in clinical samples if they are subcultured before susceptibility tests.
Sujets
PID Serval
serval:BIB_547D1AEC93C1
PMID
Open Access
Oui
Date de création
2012-04-01T12:55:41.696Z
Date de création dans IRIS
2025-05-20T17:58:39Z
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Nom
REF.pdf
Version du manuscrit
published
Taille
401.1 KB
Format
Adobe PDF
PID Serval
serval:BIB_547D1AEC93C1.P001
URN
urn:nbn:ch:serval-BIB_547D1AEC93C16
Somme de contrôle
(MD5):7aa4da7f9a34d6a1982b8f2cf9aeae80