Bacteriology and resistance patterns of otitis media with effusion

Following the increased use of antibiotics, the emergence of antibiotic-resistant species in pediatric patients with otitis media has become a problem in recent years. The aim of this study was to investigate change in bacterial species, antibiotic resistance, and detection rate of highly pathogenic species, such as Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa according to the number of repeated ventilation tube insertion (VTI) procedures in pediatric patients diagnosed with otitis media with effusion (OME).

From May 2010 to June 2018, 158 patients under 17 years of age who were admitted to the outpatient clinic of Kyung Hee Medical Center and diagnosed as OME and underwent unilateral or bilateral VTI were included in this study. Bacterial cultures were performed on aseptically collected middle ear effusion (MEF) at the time of VTI and antibiotic sensitivity tests were performed on the identified bacteria.

Bacteria were not identified in 195 (70.1%) cultures and identified in 83 (29.9%) cultures. Coagulase-negative staphylococci (CNS) was the most frequently detected species in both the non-recurrent group and the recurrent group. MRSA detection rate was found to be significantly higher in the recurrent group than in the non-recurrent group (p = 0.029). The two groups showed no significant difference in antibiotic resistance against all antibiotics (p > 0.05).

Staphylococcus species were detected most frequently in the MEF of pediatric OME patients, and the MRSA detection rate was higher in the recurrent group than in the non-recurrent group. There was no difference in antibiotic sensitivity between the two groups against all antibiotics, but resistance to penicillin G and cefoxitin was newly appeared in patients with repeated detection of same bacterial isolates.