Antimicrobial Susceptibility Profile of Contemporary Clinical Strains ofStenotrophomonas maltophiliaIsolates: Can Moxifloxacin Activity Be Predicted by Levofloxacin MIC Results?

The susceptibility profile of 763 Stenotrophomonas maltophilia isolates was evaluated against 16 antimicrobials by the CLSI reference broth microdilution method. Minocycline (MIC(90), 1 microg/ml; 100.0% susceptible) was the most active compound, followed by doxycycline (MIC(90), 4 microg/ml; 99.6% susceptible), trimethoprim/sulfamethoxazole (MIC(90), 1 microg/ml; 97.8% susceptible), and tigecycline (MIC(90), 2 microg/ml). An excellent correlation between levofloxacin (MIC(90), 4 microg/ml; 86.5% susceptible by published breakpoint criteria) and moxifloxacin (MIC(90), 2 micro g/ml) MIC results was observed indicating that moxifloxacin could be further evaluated as a therapeutic option for S. maltophilia infections.