Pathogenic Potential of and : A Case Report.

and have been considered normal aural flora. Their significance in active infection is controversial. We examined a series of patients presenting with acute and chronic otitis media whose ear canal culture isolated and and explored possible pathogenicity, associated factors, and outcomes. This is a retrospective chart review of patients who presented to a tertiary center outpatient clinic between 2017 and 2022 with otologic microscopic examination of active infection and ear canal culture isolating or only. Clinical course was collected including history, microscopic otoscopy findings, interventions given, outcomes, and sensitivity results. A total of 13 patients (10 with and 3 with ) were included. Majority of the patients had a history of otologic surgery (92%) and tympanic membrane perforation (62%). All were treated with combinations of antibiotic otic drops (ie, fluoroquinolone, sulfa, or aminoglycoside based) ± oral antibiotics (ie, penicillin or trimethoprim/sulfamethoxazole). Otorrhea resolved among majority of patients. Otorrhea and mucosalization returned or continued among 4 patients. Sensitivity results demonstrated that 2 of 3 strains of were resistant to clindamycin. There was no resistance against for tested antibiotics. Our findings suggest the potential pathogenicity of and , especially among patients with prior ear surgery and tympanic membrane perforation. Violation of the epithelial barrier from surgery or trauma may contribute to their pathogenicity. Future study is warranted to elucidate pathogenicity of normal aural flora and its mechanisms.