BACTERIOLOGICAL ACTIVITY OF TROVAFLOXACIN, A NEW QUINOLONE, AGAINST RESPIRATORY-TRACT PATHOGENS

The use of established fluoroquinolones, such as ciprofloxacin and ofl oxacin, as empirical therapy for the treatment of moderate-to-severe r espiratory tract infections is limited by their poor activity against gram-positive and atypical pathogens. Data from in vitro susceptibilit y studies and in vivo animal protection models suggest that the new fl uoroquinolone, trovafloxacin, compared with ciprofloxacin and ofloxaci n offers equivalent activity against gram-negative pathogens and impro ved activity against gram-positive pathogens. In particular, susceptib ility data indicate that trovafloxacin is at least 16-fold more potent than either ciprofloxacin or ofloxacin against penicillin-susceptible and penicillin-resistant strains of Streptococcus pneumoniae. Other s usceptible pathogens include Streptococcus pyogenes, vancomycin-suscep tible Enterococcus faecalis and the atypical respiratory pathogens Leg ionella pneumophila, Mycoplasma pneumoniae and Chlamydia pneumoniae. I n vivo studies involving models of protection against acute systemic i nfection and pneumococcal pneumonia in mice, and Legionnaires' disease in guinea pigs, indicate that the antibacterial spectrum observed for trovafloxacin in vitro extends to the in vivo setting. Together, thes e findings suggest that trovafloxacin may offer clinical efficacy agai nst respiratory pathogens superior to that of ciprofloxacin and of ofl oxacin, and may find a useful role as empiric therapy in both the comm unity and hospital setting.