ABSTRACT
A gerbil model of acute otitis media induced by Streptococcus pneumoniae plus Haemophilus influenzae was used to assess the efficacy of amoxicillin/clavulanic acid (A/C) (1.5/0.3, 2.5/0.5 and 10/2 mg/kg) and erythromycin (2.5, 10, 20 and 50 mg/kg) with or without acetaminophen. The amoxicillin/clavulanic acid MIC was 1/0.5 mg/l for both organisms and the erythromycin MICs were 0.12 and 4 mg/l for S. pneumoniae and H. influenzae, respectively. The organisms were inoculated directly into the middle ear (ME) and antibiotic treatment started 2 h post-inoculation and continued at 8h intervals for three doses. Acetaminophen was administered at 50 mg/kg. Samples for bacterial counting were obtained from the ME on day 2. Amoxicillin/clavulanic acid peri-MIC concentrations in ME were effective in eradicating both organisms. Despite the inflammation induced by S. pneumoniae, erythromycin did not eradicate H. influenzae at ME concentrations (2.4 mg/l for erythromycin 50 mg/kg) higher than those obtained in humans but lower than the MIC.
Subject(s)
Amoxicillin-Potassium Clavulanate Combination/therapeutic use , Erythromycin/therapeutic use , Haemophilus Infections/drug therapy , Otitis Media/drug therapy , Pneumococcal Infections/drug therapy , Animals , Disease Models, Animal , Drug Therapy, Combination , Gerbillinae , Haemophilus influenzae/drug effects , Haemophilus influenzae/isolation & purification , Microbial Sensitivity Tests , Otitis Media/metabolism , Otitis Media/microbiology , Pneumococcal Infections/complications , Pneumococcal Infections/microbiology , Streptococcus pneumoniae/drug effects , Streptococcus pneumoniae/isolation & purificationABSTRACT
Amoxicillin at doses of 0.2 to 5 mg/kg of body weight was administered for the treatment of pneumococcal otitis media in a gerbil model. Doses greater than or equal to 2.5 mg/kg, which resulted in concentrations in middle ear fluid of > or = 1.4 microg/ml and concentrations in serum higher than the MIC (1 microg/ml) for > or = 14% of the dosing interval, were both clinically and bacteriologically effective.