Cefdinir is a widely used orally administered cephalosporin for community-acquired respiratory tract infections and skin and soft tissue infections (SSTI). A total of 415 nonduplicate isolates of community-acquired SSTI (CA-SSTI) were collected from medical centers in North America and susceptibility tested against cefdinir and various compounds indicated for the treatment of CA-SSTI. The cefdinir MIC(50/90) in microg/mL/% susceptible for strains of the 7 principal CA-SSTI pathogens were: oxacillin-susceptible Staphylococcus aureus (0.5/0.5/100%), oxacillin-susceptible coagulase-negative staphylococci (0.06/0.12/100%), group A streptococci (< or =0.03/< or =0.03/100%), group B streptococci (< or =0.03/0.06/100%), viridans group streptococci (0.25/2/88%), Klebsiella spp. (0.12/1/95%), and Escherichia coli (0.25/0.5/95%). Cefdinir was the most potent oral cephalosporin tested against staphylococci and the Enterobacteriaceae species, and 8-fold to 64-fold more potent than cephalexin against these pathogens. Beta-Hemolytic streptococci was highly susceptible to cefdinir (MIC(90), < or =0.03-0.06 microg/mL), while viridans group streptococci showed slightly elevated MIC results. Cephalexin MIC values for streptococcal strains (MIC(90), 1-32 microg/mL) were 32-fold to 64-fold higher than those of cefdinir or other oral cephalosporins evaluated. Only 0.5% of all 415 recent CA-SSTI pathogens were resistant to cefdinir (MIC, > or = 4 mg/L). Cefdinir showed a spectrum and potency comparable or superior to other orally administered beta-lactams (cephalexin).