Bacteriologic efficacy of a three-day intramuscular ceftriaxone regimen innonresponsive acute otitis media

Objective. To determine the bacteriologic efficacy of ceftriaxone in nonres ponsive acute otitis media in children. Methods. In a prospective study 92 patients ages 3 to 36 months (median, 11 months) with culture-proved nonresponsive acute otitis media were studied from January, 1995, through August, 1997, The patients were treated with in tramuscular ceftriaxone (50 mg/kg/I/day) for 3 days. Middle ear fluid was a spirated for culture by tyrmpanocentesis on day of enrollment (Day 1); a se cond tap was performed on Days 4 to 10. Additional middle ear fluid culture s were obtained if clinical relapse occurred. Bacteriologic failure was def ined by positive culture on Days 4 to 10, Patients were followed until Day 17 +/- 2, Susceptibility was measured by E test. Results. The main drugs administered before enrollment were amoxicillin (38 %), amoxicillin-clavulanate (25%) and. cefaclor (20%). Organisms recovered (n = 105) were: Haemophilus influenzae, 54; Streptococcus pneumoniae, 47; M oraxella catarrhalis, 2; and Streptococcus pyogenes, 2. Thirty-four (72%) o f the 47 S, pneumoniae isolates were intermediately resistant to penicillin (MIC 0.1 to 1.0 mu g/ml), but all were susceptible to ceftriaxone (MIC < 0 .5 mu g/ml). Bacteriologic eradication was achieved in 100 of 105 (95%) cas es: 54 of 54 (100%) H. influenzas, 43 of 47 (92%) S. pneumoniae, 1 of 2 (50 %) NL catarrhalis and 2 of 2 (100%) S. pyogenes, Bacteriologic success (wit h no relapse) occurred in 13 of 13 (100%) penicillin-susceptible S. pneumon iae vs. 28 of 34 (82%) S. pneumoniae intermediately resistant to penicillin (4 cases of bacteriologic failure and 2 cases of relapse). Conclusion. A 3-day intramuscular ceftriaxone regimen is efficacious for th e treatment of nonresponsive acute otitis media. The optimal duration of tr eatment in cases of nonresponsive acute otitis media and whether ceftriaxon e is efficacious for the treatment of nonresponsive otitis media caused by S, pneumoniae highly resistant to penicillin is yet to be determined.