Comparative in vitro activities of three new quinolones and azithromycin against aerobic pathogens causing respiratory tract and abdominal wound infections.

BACKGROUND: In our study the in vitro susceptibility of common pathogens that cause respiratory tract and abdominal wound infections was tested against two newer fluorquinolones (moxifloxacin and gatifloxacin) as well as levofloxacin and azithromycin. METHODS: 50 isolates each of methicillin-susceptible Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, Streptococcus pneumoniae, Streptococcus pyogenes, Escherichia coli, Pseudomonas aeruginosa and Haemophilus influenzae isolated from the respiratory tract and from wounds were tested for their susceptibility to moxifloxacin, gatifloxacin, levofloxacin and azithromycin. RESULTS: Moxifloxacin proved to be the most active substance against the tested gram-positive pathogens. Gatifloxacin was the most active against P. aeruginosa. Moxifloxacin and gatifloxacin proved to be comparably active against the clinical isolates of E. coli and H. influenzae. CONCLUSIONS: Moxifloxacin and gatifloxacin display excellent activity against respiratory pathogens as well as nosocomial pathogens causing abdominal wound infections. When treating infections caused by P. aeruginosa the earlier fluorquinolones such as ciprofloxacin or ofloxacin are the substances of choice.