Bacteriology of medically refractory acute otitis media in children: a 9-year retrospective study

To identify the causative organisms for medically refractory acute otitis media (AOM) in children, and to recommend the appropriate antibiotics for these patients.

Retrospective chart review.

The medical records for 671 children (1258 ears) undergoing myringotomies between January 1993 and December 2001 were retrospectively reviewed. "Medically refractory" AOM is defined as AOM requiring emergency myringotomy because of toxicity persisting despite second-phase antibiotics. Of these, 18 children were enrolled in our study, with 25 of the ears affected by medically refractory AOM. Myringotomy was performed for pus drainage, bacterial culture and susceptibility studies in all cases. Clinical factors were analyzed to demonstrate possible relationships with microbiological findings.

Bacteria were recovered in specimens taken from 12 ears. The positive culture rate was 48%. Bacteriological studies showed mostly growing gram-positive bacteria, such as coagulase negative staphylococcus, Staphylococcus aureus and Streptococcus pneumoniae (in decreasing order of incidence). The sensitivity rate to pre-myringotomy antibiotics was 85.7%. With the exception of Pseudomonas aeruginosa and two ears with intracranial complications or pneumonia, all other isolated microorganisms were susceptible to first-generation cephalosporins. No statistically significant differences were noted between culture rates and clinical factors.

The distribution of organisms in our medically refractory AOM cases differed from that for simple AOM, with gram-positive bacteria having significantly higher rates of incidence. Combining intravenous aminoglycoside with first-generation cephalosporin is considered an inexpensive and effective treatment covering all potential microorganisms. Vancomycin or third-generation cephalosporins are only needed for major complications or other coincident infections extant during the initial presentation.