Microbial flora of mastoid cavity after canal wall down (CWD) mastoidectomy

Introduction: Many scientists have worked on microbial flora of the ear canal or middle ear in nonoperated patients, but it is not clear that what changes would be occurred in the flora of the mastoid cavity postoperatively. It can help the surgeons to choose the appropriate drugs in the perioperative period. The study was designed to investigate the microbial flora of the middle ear and mastoid cavities after canal wall down (CWD) mastoidectomy. Materials and Methods: The survey was designed as a prospective cross-sectional study. All patients with chronic otitis media who had undergone CWD mastoidectomy in a public university hospital from 2014 to 2017 were enrolled in the study. They were periodically followed up postoperatively at least for 6 months. Swab sampling from ear cavity was performed, and the samples were sent for culture and antibiogram. Each specimen was sent for bacterial and fungal analysis. If bacterial culture result was positive, the sensitivity of the cultured organisms to common antibiotics was also assessed. Results: Seventy-four patients entered into the survey. Twenty-six (35%) of samples were positive for bacteria, and 11 (14.5%) were positive for fungi. Furthermore, 3 (4%) of the studied ears were positive simultaneously for both bacterial and fungal culture. Among cultured bacteria, Staphylococcus epidermidis was the most common species (29%). Candida species was the most common fungal species (8%). Conclusions: Microbial infection is a common finding after CWD mastoidectomy. S. epidermidis and Candida species should be considered as the primary targets of treatment.