Resistant bacteria in middle ear fluid at the time of tympanotomy tube surgery

This study was performed to determine the prevalence of resistant Streptoco ccus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis isolated from middle ear fluid of children undergoing placement of ventilation tube s. The extent of resistance to commonly prescribed antibiotics and the risk factors associated with this resistance were also examined. Children who h ad fluid present in their middle ears at the lime of ventilation tube place ment from May 1996 to May 1997 were included in the study. Middle ear fluid was plated onto culture media in the operating room, and antimicrobial res istance of cultured organisms was ascertained. Risk factors for this resist ance were determined from the medical history and analyzed. Cultures of 344 patients (355 ears) were positive for organisms in 29.6%. Penicillin resis tance was found in 38.2% of S pneumoniae cultures. beta-Lactamase productio n was found in 65.1% and 100% of H influenzae and M catarrhalis specimens, respectively. Risk factor analysis revealed young age, day care attendance, and number of antibiotic courses to most reliably predict the presence of resistant microorganisms.