In vitro antimicrobial activity of cefditoren and other oral antibiotics against Streptococcus pneumoniae, isolated from children with community acquired respiratory tract infections.

The antibacterial susceptibility to frequently prescribed antibiotics of Streptococcus pneumoniae isolated from the pediatric patients with acute respiratory infectious diseases was investigated in a study of three medical institutions in Korea. Total 143 clinical isolates of S. pneumoniae were available for susceptibility tests between May 2003 and July 2007. Antimicrobial susceptibility data for S. pneumoniae were analyzed by using agents of amoxicillin, cefaclor, cefuroxime, cefdinir, and cefditoren as the test antibiotics. The prevalence of each resistance class, penicillin-resistant S. pneumoniae (PRSP) were high with the proportion of MIC range (susceptible = 8.4%, intermediate resistance = 18.2%, resistance = 73.4%). MIC90 and susceptible (S) rate of antimicrobial agents to the strains tested were amoxicillin (MIC90 = 4 microg/ml, S = 76.2%), cefaclor (MIC90 = 128 microg/ml, S=8.4%), cefuroxime (MIC90 = 16 microg/ml, S = 24.5%), cefdinir (MIC90 = 16 microg/ml, S = 21.8%), and cefditoren (MIC90 = 0.5 microg/ml, S=90.2%) respectively. Against clinical isolates including PRSP, cefditoren demonstrated the strongest antibacterial activity intrinsically among the antibiotics tested. Conclusively, the antimicrobial activity of cefditoren to S. pneumoniae strains isolated from pediatric patients with acute respiratory infection is very high. In South Korea, where the antibiotic resistance ofS. pneumoniae is issued, cefditoren is expected to be used as a primary or secondary antibiotic. Moreover, cefditoren may serve as a useful option for secondary antibiotics after failure of amoxicillin treatment, which is most primarily used for acute respiratory S. pneumoniae infection in children.