Skip Navigation



JAC Advance Access published online on June 19, 2008
Journal of Antimicrobial Chemotherapy, doi:10.1093/jac/dkn266
This Article
Right arrow Full Text Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow All Versions of this Article:
62/4/766    most recent
dkn266v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Woodford, N.
Right arrow Articles by Livermore, D. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Woodford, N.
Right arrow Articles by Livermore, D. M.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© The Author 2008. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oxfordjournals.org

Original research

In vitro activity of retapamulin against Staphylococcus aureus isolates resistant to fusidic acid and mupirocin

N. Woodford*, M. Afzal-Shah, M. Warner and D. M. Livermore

Antibiotic Resistance Monitoring and Reference Laboratory (ARMRL), HPA Centre for Infections, London NW9 5EQ, UK

Received 27 May 2008; returned 4 June 2008; revised 1 June 2008; accepted 5 June 2008

* Corresponding author. Tel: +44-20-8327-7255; Fax: +44-20-8327-6264; E-mail: neil.woodford{at}hpa.org.uk

Objectives: We determined the in vitro activity of retapamulin, a novel pleuromutilin antibiotic, against 664 Staphylococcus aureus isolates from the UK, including many resistant to fusidic acid and/or highly resistant to mupirocin.

Methods: MICs were determined on Mueller–Hinton agar in accordance with the CLSI guidelines. Susceptibility was categorized using CLSI criteria, where available; otherwise the European Committee for Antimicrobial Susceptibility Testing (EUCAST)/BSAC criteria were used (for mupirocin and fusidic acid). Mutations in the rplC gene, which encodes ribosomal protein L3, were sought by PCR and DNA sequencing.

Results: The S. aureus included 488 (73%) methicillin-resistant isolates (oxacillin MICs >2 mg/L), 336 isolates (51%) resistant to fusidic acid (MICs >1 mg/L) and 254 (38%) with high-level mupirocin resistance (MICs >256 mg/L); 103 (16%) isolates were resistant both to fusidic acid and to high levels of mupirocin. Retapamulin inhibited 663 (99.9%) isolates at ≤0.25 mg/L. A single methicillin-resistant S. aureus isolate, also with high-level mupirocin resistance, required a retapamulin MIC of 2 mg/L, but its reduced susceptibility to retapamulin was not associated with any mutation in ribosomal protein L3.

Conclusions: Retapamulin demonstrated excellent activity in vitro against S. aureus isolates, irrespective of their level of resistance to other antibacterials. These results support the EUCAST epidemiological cut-off value for retapamulin of ≤0.5 mg/L against S. aureus.

Key Words: S. aureus , MRSA , mechanisms


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.