Turicella otitidis Extra-otic Infections in Humans - a Narrative Review

Turicella otitidis is a Gram-positive bacillus, commensal inhabitant of the external auditory canal. It is the causative agent of external otitis and otitis media. Extra-otic infections are rarely been identified especially in patients with comorbidities. A narrative review was performed based on a search of PubMed/Medline and Scopus databases to collect information on the epidemiologic, clinical and microbiologic data of extra-otic infections by T. otitidis . Studies published until December 2024 were screened and analyzed to extract data on pathogen characteristics, antibiotic resistance profiles, treatment and outcomes. A total of 13 studies reporting infections by T. otitidis other than otitis including an equal number of patients were eligible. The mean age of patients was 34.08 years (range, 3-75 years). A male predominance was observed (1.6:1). Four patients were immunocompromised and four underwent recent surgical procedures. The most common infection type was bacteremia (38.4%), followed by abscesses, mastoiditis, ocular infections and skin and soft tissues infections. In the majority of cases (63.6%) a single method of identification was applied, such as matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS), polymerase chain reaction (PCR), Vitek 2 automated system and analytical profile index (API) Coryne. Antimicrobial resistance to erythromycin was 80%, while all isolates were susceptible to vancomycin. Vancomycin (45.5%) and cephalosporins (45.5%) were the most commonly used antimicrobials. In all cases with available data, the outcome was favorable. T. otitidis is an emerging pathogen causing extra-otic infections in humans, especially in the presence of predisposing conditions. Future studies are warranted to elucidate the microorganism's pathogenicity and the factors and mechanisms underlying its virulence.