The effect of cefaclor and cefixime on nasopharyngeal pathogens in children

Abstract

Changes in nasopharyngeal flora were investigated in children with acute otitis media and with acute exacerbations of chronic sinusitis in whom antibiotic therapy of relatively long duration was required until substantial improvement in clinical findings was achieved. 1. The antibiotics used were two cephalosporins, i.e., cefaclor (CCL) and cefixime (CFIX), administered to 18 patients each for 1 week and to 26 and 20 patients, respectively, for 2 weeks. Bacteriologic examination of the nasopharyngeal mucosa was performed at the first visit and at 1 week in those who underwent antibiotic therapy for 1 week, and at the first visit and at 1 and 2 weeks in those treated with antibiotics for 2 weeks. 2. The elimination rates for the infecting microorganisms in the patients in the CCL-treated group were 30% for Haemophilus influenzae. 83% for Staphylococcus aureus, 100% for Streptcoccus pyogenes and 100% for Streptcoccus pneumoniae at 1 week, and 18% for H. influenzae, 100% for S. aureus and 100% for S. pyogenes at 2 weeks of antibiotic therapy. Replacement of S. aureus and S. pyogenes by H. influenzae was observed. 3. The elimination rates for infecting bacteria in the patients in the CFIX-treated groups were 61% for H. influenzae. 50% for S. aureus, 75% for S. pyogenes, 80% for S. pneumoniae and 100% for Moraxella catarrhalis at 1 week, and 72% for H. influenzae, 0% for S. aureus, 100% for S. pyogenes, and 0% for S. pneumoniae at 2 weeks of antibiotic therapy. The elimination rate for H. influenzae at 2 weeks was significantly higher than the corresponding value for the CCL-treated group. Replacement of H. influenzae by S. aureus and S. pneumoniae and of S. pyogenes by S. aureus was detected. 4. There was one patient with acute otitis media in the CFIX-treated group in whom a clinical relapse occurred due to H. influenzae persisters in the nasopharynx. Thus the diagnosis in this patient was so-called “recurrent otitis media”. 5. H. influenzae tended to persist after exposure to therapeutically adequate concentrations of CCL, as did S. aureus and S. pneumoniae following treatment with CFIX. Thus, it would seem that ample heed must be given to persistence, particularly of H. influenzae and S. pneumoniae, the most common causative agents of acute otitis media in childhood. 6. A significant rise in the MICs of the cephalosporins was observed in 4 of 43 patients in whom the same type of organism was isolated from the nasopharynx at weekly intervals during antibiotic therapy. Since cephalosporin therapy brought about a substantial improvement in clinical symptoms in all 4 of these patients with a definite reduction in the infecting bacterial population, the development of drug resistance was considered to be due to selection of a small number of resistant strain among the drug susceptible majority of the microbial population against which the cephallosporins were destructive. © 1995, The Oto-Rhino-Laryngological Society of Japan, Inc. All rights reserved.