In Vitro Killing Effect of Moxifloxacin on Clinical Isolates of Stenotrophomonas maltophilia Resistant to Trimethoprim-Sulfamethoxazole

The time-kill effect of moxifloxacin on 20 genetically distinct isolates of Stenotrophomonas maltophilia resistant to trimethoprim-sulfamethoxazole was studied. The majority (80%) were killed by a concentration equivalent to four times the MIC; the MIC induced a transient decrease in bacterial counts at 4 h, followed by regrowth. No effect was detected in four isolates. These results merit further clinical consideration.