Unusual case of otomycosis caused by Saksenaea vasiformis

Etiology, Predisposing Factors, Clinical Features and Diagnostic Procedure of Otomycosis: A Literature Review

Otomycosis (OM) is a superficial fungal infection of the external auditory canal (EAC) with a worldwide prevalence ranging from 9% to 30%. Commonly, otomycoses are caused by Aspergillus (A.) niger complex and Candida spp. Other causative agents are yeasts of the genera Cryptococcus spp., Rhodotorula spp., Geotrichum candidum, dermatophytes (Trichophyton mentagrophytes), and non-dermatophytes molds (Fusarium spp., Penicillium spp., Mucorales fungi). The widest range of different species causing OM are found in the territories of Iran, India, China, Egypt, Mexico, and Brazil. Fungal infection of the EAC varies from mild to severe forms. It can be acute, subacute, or chronic, and is often unilateral, while the bilateral form is more common in immunocompromised patients. From an epidemiological point of view, tropical and subtropical climates are the most significant risk factor for the development of otomycosis. Other predisposing conditions include clothing habits, EAC hygiene practices, long-term antibiotic therapy, diabetes, and immunodeficiency. Since it is often difficult to distinguish otomycosis from an infection of a different origin, laboratory-based evidence, including standard procedures (microscopy and cultivation), is essential for diagnosis. For the treatment of this superficial fungal infection, there are no official therapeutic guidelines and protocols. However, many antifungals for local application, such as polyene, imidazoles, and allylamines, can be applied, as well as systemic antimycotics (triazoles) in severe forms of infection.

In Vitro Combination of Terbinafine with Ketoconazole Against Aspergillus Species with Terbinafine High MIC Values Isolated From Otomycosis

Otomycosis is a common mycotic infection of the external auditory canal, and Aspergillus species are one of the most frequent causative agents worldwide. The limited antifungal arsenal, the high toxicity and side effects of antifungal agents, and the growing resistance to the currently available antifungals underscore the need for new therapeutic strategies. The present study aimed to evaluate the combined in vitro efficacy of terbinafine and ketoconazole against Aspergillus species with terbinafine high MIC values isolated from patients with otomycosis.84 Aspergillus species with high MIC values to terbinafine (≥ 4 µg/ml), consisting of A. flavus, A. tubingensis, A. niger, and A. terreus, were included in this study. The checkerboard microdilution method evaluated the in vitro interactions using the CLSI reference technique. Synergistic effects were observed for 66.67% (56/84) of all isolates (FICI ranging from 0.19 to 0.5). However, the interactions of terbinafine and ketoconazole exhibited indifference in 33.33% (28/84) of the isolates, and no antagonism was observed for any combination. The interaction of terbinafine and ketoconazole showed synergistic activity against Aspergillus species with high MIC values, suggesting that this is an alternative and promising approach for treating otomycosis.

Otomycosis caused by the cryptic and emerging species Aspergillus sydowii: two case reports

Two cases of otomycosis have been reported in patients undergoing tympanomastoidectomy. The first one had chronic otitis media, hypertrophic concha and nasal septum deviation, tympanic perforation and otorrhea. The second had otalgia, pruritus, chronic otitis media and cholesteatoma. Direct examination showed mycelial septate filaments with a branch at an angle close to 45°, later identified as Aspergillus sydowii by sequencing the BenA and CaM genes. Susceptibility testing showed low MIC of amphotericin B, itraconazole, ketoconazole and ciclopirox olamine. In both cases, ketoconazole was instituted for 10 days. Otomycosis is a challenge as it is primarily recurrent in patients undergoing surgery. The clinical implication, the identification of the emerging pathogen and the determination of MIC were necessary for the knowledge of the epidemiological profile and establishment of the treatment.