Basic and clinical studies on cefdinir in respiratory infections

We quantitated the in vitro antimicrobial activity, and the plasma and sputum concentrations of cefdinir (CFDN), a new oral cephem antibiotic, and evaluated its therapeutic efficacy in respiratory infections. The minimum inhibitory concentrations (MICs) of CFDN, cefaclor (CCL), cefixime (CFIX) and amoxicillin (AMPC) against 20 strains each of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Serratia marcescens and Pseudomonas aeruginosa were determined by a microbroth dilution method using the Dynatech MIC 2000 system. As shown by MICs, CFDN was more active against S.aureus than the other antibiotics, was as active as CFIX and more active than CCL and AMPC against E.coli and E. cloacae. CFDN was less active against K.pneumoniae and S.marcescens than CFIX, and was not as potent as the other agents against P.aeruginosa. The concentration of CFDN in the plasma of 2 patients with chronic respiratory tract infections, was highest at 4 hours after oral administration of 200mg (2.58 and 3.39μg/ml). The highest concentration of CFDN in the sputum of one patient was 0.032μg/ml, at 6~8h after oral administration, but its concentration was below the level of detection in the sputum of the other patient. A dialy dose of 300~600mg of CFDN was given orally for 3′14 days to 31 patients: 2 with acute pharyngitis, 6 with acute bronchitis, 5 with chronic respiratory infections, 16 with acute pneumonia and 2 with infection supervening on lung cancer. The clinical efficacy in the 29 patients (except 1 each with Mycoplasma pneumoniae pneumonia and lung cancer) wasexcellent in 1, good in 21, fair in 2 and poor in 5, with an efficacy rate of 75.9%. One patient with lung cancer was excluded from the evaluation because of the lack of symptoms and signs of infections. Eighteen strains were identified as causative organisms, and 14 of these were eradicated by CFDN. A transient elevation of s-GOT and s-GPT was observed in 4 patients. Eosinophilia was observed in 3 and leucocytopenia in 2 patients. The adverse reactions disappeared after completion of the therapy. From the above results, we conclude that CFDN is one of the most useful oral antibiotics as a first choice in the treatment of respiratory infections.