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Video

Otology/Neurotology

(A869) Understanding the Microbiology of Chronic Otitis Media

Monday, October 13, 2025
12:00 PM - 1:00 PM EDT
Location: OTO EXPO, Posters
Has Audio
Disclosure(s):
Erika M. Celis-Aguilar, MD: No relevant relationships to disclose.
Melissa Angulo-Altamirano, MD: No relevant relationships to disclose.
Graciela Ibarra-Armenta: No relevant relationships to disclose.
Alan Yovni Valle-Obeso: No relevant relationships to disclose.
Evangelina Sotolongo-Barroso, MD: No relevant relationships to disclose.
Bryan Santiesteban-Guevara, MD: No relevant relationships to disclose.


Introduction:

Objective: To describe the microbiology of Chronic Otitis Media (COM) and the susceptibility and resistance patterns.

Methods: This is a clinical chart review conducted in a secondary Care Center.
Patients with COM who attended the clinic between October 2021 and July 2023 were included. Clinical data, along with results from bacterial and fungal cultures, were collected. Antibiotic susceptibility testing was performed on the bacterial isolates.
A descriptive analysis was conducted.

Results: Twenty-one patients diagnosed with COM were included, fourteen female patients, with a mean age of 50.65 years. Fifty-two percent (n=11) had cholesteatoma. The most frequently isolated microorganisms were Corynebacterium amycolatum (17%, n=8), Staphylococcus coagulase-negative (12.7%, n=6), Pseudomonas aeruginosa (10.6%, n=5), and Staphylococcus aureus (6.3%, n=3). Isolated fungi were Candida albicans (12.5%, n=2), Candida parapsilosis (37.5 %, n=6), and Aspergillus terreus (18.7%, n=3). A high resistance was observed to lincosamides (75%), macrolides 58.3%, penicillins 45.8%, and quinolones 44.1%. High susceptibility was observed to carbapenems, oxazolidinones, and 72.9% to cephalosporins. Regarding the bacterial spectrum, Corynebacterium amycolatum showed 100% susceptibility to cefotaxime, tetracycline, and linezolid, with 83% resistance to levofloxacin. Pseudomonas were susceptible to gentamicin, amikacin, cefepime, ceftazidime, and meropenem, but resistant to cephalothin, ceftriaxone, and fosfomycin. S. aureus was highly susceptible to vancomycin, nitrofurantoin, trimethoprim/sulfamethoxazole, linezolid and 33% resistance to ciprofloxacin and erythromycin.

Conclusions: Corynebacterium amycolatum was the most common isolated microorganism.we found an increase antibiotic resistance to commonly used drugs such as fluoroquinolones, macrolides and penicillins. This study highlights the need for targeted therapy based on local resistance patterns. Further research on biofilms and fungal roles in COM is warranted.