Evaluation of trovafloxacin in the treatment of Klebsiella pneumoniae lunginfection in tumour-bearing mice

Trovafloxacin, a new trifluoroquinolone, was evaluated for its therapeutic efficacy against Klebsiella pneumoniae lung infection in tumour (P388 murin e leukaemia cells)-bearing mice, treated with or without a chemotherapeutic agent, daunorubicin (DNR) and in mice without tumour. Its activity was com pared with ciprofloxacin and cephazolin. The effect on therapeutic efficacy of the addition of recombinant granulocyte colony stimulating factor (rGCS F) was also examined. Our study showed that both quinolones successfully cu red pneumonia owing to infection with K. pneumoniae in mice without tumours but that ail antibiotics failed in tumour-bearing mice if DNR was withheld . Substantial differences were noted in DNR-treated tumour-bearing mice wit h infection-the cure rate with trovafloxacin was 91% whereas the cure rate with ciprofloxacin or cephazolin was 57%. Addition of rGCSF to ciprofloxaci n did not substantially improve its efficacy (when assessed by protection a gainst death owing to infection; the survival rate was 41%). Trovafloxacin cure rates ranged from 80 to 90% whether or not rGCSF was added to the trea tment regimen. Our results suggest that prior cancer chemotherapy had no ad verse effect on the therapeutic efficacy of trovafloxacin, and that trovafl oxacin may be a promising therapeutic agent for treatment of bacterial infe ctions in the presence of leucopenia.