The Role of Bacteriologic Studies in Predicting Recurrent Mastoiditis in 456 Patients

Objectives: To evaluate the effect of microbiologic growth on the recurrence rate of mastoiditis. Materials and Methods: A historical prospective study on all cases of children with acute mastoiditis (AM) admitted between 2000 and 2015, was performed. The following data were collected in the recurrent AM (rAM) group: age, sex, and medical history, antibiotic therapy before hospitalization, clinical presentation at admission including symptoms and signs, blood test results, computed tomography (CT) imaging, microbiological findings, treatment, complications, outcome, and follow-up duration. Results: Four hundred fifty six consecutive hospitalizations because of mastoiditis were identified; 22 patients were found to have rAM. The median age at first episode in the rAM group was 1 year (range, 1-11 years), and the median period from one episode to the next was 2 months. There were 15 men and 7 women. The right ear was involved in 11 cases in the first and in the second episode. The rate of Pseudomonas aeruginosa growth in the rAM group was significantly higher compared with the AM group (40.9 and 8.9%, respectively) (p = 0.001) as was found in anerobic growth (15 vs. no growth) (p < 0.001) and in polymicrobial growth (59% vs. 3.6%) (p < 0.001). Conclusion: Patients with P. aeruginosa growth, anaerobic bacteria, and polymicrobia infection cultured in an AM infection, are prone to have rAM, and therefore antibiotic adjustments according to their bacteriologic studies should be considered even if clinical improvement is encountered, or surgical intervention during the first AM episode, and closer follow up with proper antibiotic treatment when signs of recurrent ear infection are encountered.