Open Access Open Badges Research article

Sub-inhibitory concentrations of vancomycin prevent quinolone-resistance in a penicillin-resistant isolate of Streptococcus pneumoniae

Philippe Cottagnoud1*, Jose M Entenza2, Marianne Cottagnoud3, Yok-Ai Que2, Philippe Moreillon2 and Martin G Täuber4

Author Affiliations

1 Department of Internal Medicine, Inselspital, Freiburgstrasse, CH-3010 Berne, Switzerland

2 Division of Infectious Diseases, Department of Internal Medicine, Centre Hospitalier Universitaire Vaudois, CH-1011 Lausanne, Switzerland

3 Department of Internal Medicine, Spital Bern Ziegler, Morillonstrasse 75-91, CH-3007 Berne, Switzerland

4 Institute for Infectious Diseases, University of Berne, CH-3010 Berne, Switzerland

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BMC Microbiology 2001, 1:9  doi:10.1186/1471-2180-1-9

Published: 2 July 2001



The continuous spread of penicillin-resistant pneumococci represents a permanent threat in the treatment of pneumococcal infections, especially when strains show additional resistance to quinolones. The main objective of this study was to determine a treatment modality impeding the emergence of quinolone resistance.


Exposure of a penicillin-resistant pneumococcus to increasing concentrations of trovafloxacin or ciprofloxacin selected for mutants resistant to these drugs. In the presence of sub-inhibitory concentrations of vancomycin, development of trovafloxacin-resistance and high-level ciprofloxacin-resistance were prevented.


Considering the risk of quinolone-resistance in pneumococci, the observation might be of clinical importance.