In vitro activity of cefdinir (FK482) and ten other antibiotics against gram-positive and gram-negative bacteria isolated from adult and pediatric patients.

The in vitro activity of cefdinir, an oral aminothiazolyl hydroxyimino cephalosporin was compared with that of cefixime, cefpodoxime, cefaclor, cephalexin, ciprofloxacin, ofloxacin, oxacillin, ampicillin, vancomycin and trimethoprim-sulfamethoxazole against 279 gram-positive and gram-negative recent clinical isolates from adult and pediatric patients. Cefdinir was the most active drug among the cephalosporins against oxacillin-sensitive Staphylococcus aureus and coagulase-negative staphylococci, Streptococcus pneumoniae, S. pyogenes, Escherichia coli and Moraxella catarrhalis (MIC90 0.015-2 mg/l). Cefixime was the most active agent against Hemophilus influenzae, Klebsiella pneumoniae, K. oxytoca, Proteus mirabilis and P. vulgaris (MIC90 < 0.015-0.125 mg/l). The activity of cefpodoxime was better than that of cefixime against S. pneumoniae and oxacillin-sensitive staphylococci (MIC90 0.25-8 vs. 0.5-32 mg/l), similar to cefixime against S. pyogenes (MIC90 0.06 mg/l) and not as good as cefixime against H. influenzae, M. catarrhalis, Klebsiella spp. and Proteus spp. (MIC90 < 0.015-0.25 vs. 0.125-0.5 mg/l). The activity of cefdinir was greater than that of the other cephalosporins against Enterococcus faecalis (MIC90 16-32 vs. > 64 mg/l). None of the cephalosporins were active against methicillin-resistant, coagulase-positive or -negative staphylococci or Pseudomonas aeruginosa (MIC90 > 64 mg/l). Overall, the susceptibilities of adult and pediatric isolates were similar. Kinetic kill curves demonstrated rapid and similar killing at 6 h by cefdinir, cefixime, cefpodoxime and ofloxacin. At 24 h at 1 x MIC, the least regrowth was observed with cefdinir and cefpodoxime; at 2 x MIC, suppression of growth was similar with all four drugs.