In vitro activity of cefditoren and other comparators against Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis causing community-acquired respiratory tract infections in China.Diagn Microbiol Infect Dis. 2012 Jun; 73(2):187-91.DM
The aim of this study was to evaluate the in vitro activity of cefditoren and comparators against Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis causing community-acquired respiratory tract infections (CARTIs). A total of 391 Streptococcus pneumoniae, 266 H. influenzae, and 76 M. catarrhalis were isolated from 10 centers located at 6 cities in China from January 2009 to May 2010. The microdilution method was used to determine minimum inhibitory concentrations (MICs). The pneumococci comprised 189 (48.3%) penicillin susceptible, 129 (33.0%) penicillin intermediate, and 73 (18.7%) penicillin resistant. Moxifloxacin and levofloxacin showed the highest activity (99.2% and 97.7%, respectively) against Streptococcus pneumoniae, followed by parenteral penicillin G (95.7%), cefditoren (83.1%) and amoxicillin-clavulanic acid (79.3%). Among the 266 H. influenzae isolates, 26 (9.8%) were ampicillin-resistant β-lactamase-producing strains and 24 (9.0%) were ampicillin-resistant β-lactamase-nonproducing strains (BLNAR). Most of antimicrobial agents demonstrated good activity (>97% susceptibility) against H. influenzae except ampicillin, cefuroxime, and cefaclor, which showed relatively lower activity (81.2%, 88.7%, and 88%, respectively). Cefditoren showed excellent activity with the lowest MIC(50) and MIC(90) (≤0.016/0.064 μg/mL) among all tested drugs, which is independent of β-lactamase production or ampicillin resistance. Cefditoren at a concentration of 0.5 μg/mL inhibited all BLNAR strains. Seventy of 76 isolates of M. catarrhalis produced β-lactamase. Cefditoren also showed excellent activity with MIC(90) of 0.064 μg/mL against β-lactamase-nonproducing strains and 0.5 μg/mL against β-lactamase-producing strains. In conclusion, the excellent intrinsic activity of cefditoren suggests that it may be a good choice for the treatment of CARTIs caused by Streptococcus pneumoniae, H. influenzae, and M. catarrhalis in China, while the activity should be closely monitored.