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

Department of Internal Medicine, Inselspital, Freiburgstrasse, CH-3010 Berne, Switzerland.
BMC Microbiology (Impact Factor: 2.98). 02/2001; 1:9. DOI: 10.1186/1471-2180-1-9
Source: PubMed

ABSTRACT 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.

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