Activity of gatifloxacin compared to those of seven agents against bacteria recovered from outpatients with respiratory tract infection

The in vitro activity of gatifloxacin and levofloxacin, ciprofloxacin, peni cillin, ampicillin, ampicillin-sulbactam, ceftriaxone and clarithromycin wa s evaluated against 173 S. pneumoniae strains (128, penicillin-susceptible strains; 32, intermediate penicillin- resistant strains and 13, penicillin- resistant strains), 163 H. influenzae strains (128, beta-lactamase non-prod ucer; 35, beta-lactamase producers), ill M. catarrhalis (9, beta-lactamase non-producer; 102, beta-lactamase producers), 95 Streptococcus pyogenes and 116 S. aureus strains (96, methicillin-susceptible; 20, methicillin-resist ant) recovered from outpatients with respiratory tract infection. Based upo n the MICs at which 50% and 90% of the isolates were inhibited we concluded that gatifloxacin proved to be the most active antibiotic against respirat ory pathogens, including all the penicillin-resistant pneumococci and H. in fluenzae or M. catarrhalis producing beta-lactamase. Furthermore, their MIC s against S. pneumoniae and methicillin-resistant S. aureus were lower than those of levofloxacin and ciprofloxacin. Therefore, this new fluoroquinolone displayed in vitro features that make i t suitable for treating community-acquired respiratory tract infections. (C ) 2000 Elsevier Science Inc. All rights reserved.