In vitro antimicrobial activity of cefditoren against Streptococcus pneumoniae and Haemophilus influenzae clinical isolates / 대한내과학회지

ABSTRACT

BACKGROUND: The aim of this study was to determine the in vitro activity of cefditoren, an oral third-generation aminothiazolyl cephalosporin, against Streptococcus pneumoniae and Haemophilus influenzae clinical isolates in a tertiary hospital. METHODS: We have studied the in vitro activities of cefditoren and other oral antibiotics against 120 S. pneumoniae isolates, including 80 penicillin non-susceptible isolates and 80 H. influenzae isolates from clinical specimens of patients at the Asan Medical Center. Minimal inhibitory concentrations (MICs) were determined by the agar dilution method. RESULTS: All S. pneumoniae strains tested were inhibited by 1 g/mL of cefditoren (MIC50/MIC90 0.25/1 microgram/mL; range 0.015~1 microgram/mL). The MICs were lower for penicillin-susceptible S. pneumoniae (MIC90 0.015 g/mL) as compared to penicillin-intermediate resistant (MIC90 0.5 g/mL) or penicillin- resistant strains (MIC90 1 microgram/mL). Cefditoren was active against all tested H. influenzae strains (MIC50/MIC90 0.015/0.03 microgram/mL; range <0.008~0.03 g/mL) and its activity was comparable to levofloxacin and cefixime. CONCLUSIONS: Cefditoren had an excellent activity against S. pneumoniae and H. influenzae irrespective of penicillin or ampicillin resistance, respectively. The results of this study suggest that cefditoren is a good choice of an antibiotic to use for empirical oral treatment of community-acquired respiratory tract infections.