In vitro and in vivo activity of moxifloxacin against community respiratory tract pathogens

The high prevalence of respiratory tract infections (RTIs) and the increasing resistance of causative pathogens to currently available antibiotics necessitates the development of new, more powerful antimicrobial agents. Such agents must possess a broad spectrum of antibacterial activity so as to be useful for both the empirical and specific therapy of RTIs. Moxifloxacin is one such antimicrobial agent. The drug is a new 8-methoxyquinolone that has been shown to have a wide range of activity against Gram-positive and -negative bacteria as well as against anaerobes and atypical pathogens that can cause RTIs. Moxifloxacin is also effective against both beta-lactam- and macrolide-resistant organisms and very rarely itself induces resistance under experimental conditions. This review summarises the in vitro evidence far the range of antibacterial activities of moxifloxacin, in terms of minimum inhibitory concentrations (MIC90), time-kill kinetics and post-antibiotic effects. These in vitro findings have been confirmed by animal studies. In conclusion, moxifloxacin has an effective, appropriate spectrum of antimicrobial activity and other properties that provide a foundation for its use in the therapy of RTIs.