Scedosporium apiospermum otomycosis

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.

Otomycosis: The foremost aetiological agent causing otitis externa and the antifungal susceptibility pattern in North-Western Iran

BACKGROUND

Otomycosis is considered a recurring fungal ear infection. The external auditory canal provides an appropriate and optimal situation for fungal growth.

OBJECTIVES

The study aimed to identify the causative agents of otomycosis and determine corresponding antifungal drug susceptibility patterns in north-western Iran.

METHODS

From October 2020 until November 2021, 200 patients attended an otolaryngology referral centre with otitis externa, and their ear discharge and debris were examined and cultured. The identification of the fungal agents was implemented by polymerase chain reaction-restriction fragment length polymorphism and sequencing. In vitro antifungal susceptibility testing of the isolates was conducted in accordance with the CLSI broth microdilution protocols.

RESULTS

The prevalence of otomycosis was measured 50.5% (n = 101/200). The majority of patients were in their forties (n = 35, 34.6%) and female (n = 57, 56.4%), and the most prevalent symptom was otalgia (56.4%). The most underlying factor was remarked manipulation employing a cotton swab (65.3%). Regarding fungus, Aspergillus section Nigri (58.57%) was the foremost isolate, followed by Aspergillus section Flavi (19.23%) and Candida parapsilosis (14.96%). The predominance of Aspergillus isolates had minimal in vitro sensitivity to tioconazole and nystatin. Candida species represented higher geometric mean minimum inhibitory concentrations (MIC) against nystatin. The MIC of three Aspergillus species isolates shown above the epidemiologic cut-off values (ECV) against itraconazole.

CONCLUSIONS

Otomycosis incidence surpassed in comparison with the previous study as the most common cause of otitis externa. The MIC distribution of Aspergillus species isolates against triazole antifungals is close to the defined ECVs and likely outrun it over time.

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.

Scedosporium apiospermum infections in the middle ear and mastoid: case series and review of the literature

Objectives

To present our case series and management of Scedosporium apiospermum infections of the middle ear and mastoid, and review the current literature on this rare yet potentially life-threatening condition.

Methods

Medical records of patients treated at the Royal Victorian Eye and Ear Hospital for S apiospermum middle ear and mastoid infections between 2009 and 2019 were reviewed. A literature search was conducted using PubMed, Medline and Cochrane Library databases.

Results

Two patients were identified in our institution: a 62-year-old diabetic woman with otogenic skull base osteomyelitis, and a 12-year-old boy with unilateral chronic suppurative otitis media which developed after tympanostomy tube insertion. The persistence of otalgia and otorrhoea despite prolonged antibiotic treatment characterised these cases. Both patients received voriconazole, and achieved disease resolution without complications. Ten relevant cases were identified after review of the literature. Despite treatment, there were three patient deaths, and four patients with otological or neurological complications.

Conclusion

The presence of a middle ear or mastoid infection refractory to appropriate topical and systemic antibiotics should prompt clinicians to consider a fungal infection. The role of surgical debridement in the treatment of S apiospermum infection of the middle ear and mastoid is equivocal.

The Role of Routine Culture in the Treatment of Chronic Suppurative Otitis Media: Implications for the Standard of Care in Rural Areas of South Africa

Chronic Suppurative Otitis Media (CSOM) is a widely prevalent disease, which is a leading cause of acquired deafness worldwide, and is associated with complications with significant mortality and morbidity. It often responds poorly to standard of care therapy and places a disproportionate burden on at-risk populations. The microbiology and antibiotic resistance of CSOM varies based on local factors, including health care access, comorbidities, and antibiotic prescribing practices. We evaluated the role and feasibility of using routine culture for the treatment of CSOM in rural areas as a means of improving treatment of CSOM. More than 400 patients were screened in a rural clinic in South Africa over six weeks, and 14 met study criteria and consented for participation. Gram-negative organisms predominated overall, although Staphylococcus aureus was the most commonly isolated single species. A majority of the pathogens were relatively sensitive to commonly prescribed antibiotics, but two cases of methicillin resistant Staphylococcus aureus were cultured, and one patient grew a Scedosporium species. Treatment on follow-up was able to be directed by culture results, suggesting routine culture at the initial point of contact with the health care system may play a pivotal role in addressing this widely prevalent and devastating disease.

Scedosporium apiospermum invasive sinusitis presenting as extradural abscess

INTRODUCTION

Chronic invasive fungal rhinosinusitis (CIFR) is a rare entity generally observed in immunodepressed subjects. The pathogen most frequently identified is Aspergillus spp. Imaging generally reveals invasive pseudoneoplastic features. We report a case of Scedosporium apiospermum (S. apiospermum) CIFR with an atypical clinical and radiological presentation.

CASE REPORT

A 72-year-old immunocompetent man presented with chronic headache, neck pain and bilateral limitation of lateral gaze. Imaging revealed an isolated left sphenoidal lesion with marked bone changes and an extradural abscess over the clivus. Large endoscopic sphenoidotomy with type II rhinopharyngectomy was performed and the diagnosis of S. apiospermum CIFR was based on histological examination and fungal culture. The patient refused all medical treatment and did not present any signs of recurrence after 1 year of follow-up.

DISCUSSION

S. apiospermum is a fungal species rarely isolated in CIFR. The present case was revealed by an atypical clinical presentation including isolated sphenoidal infection complicated by bilateral abducens nerve paralysis and extradural abscess. Imaging was also unusual, revealing features of fibrous dysplasia or bacterial osteomyelitis rather than the typical pseudoneoplastic appearance. The patient was successfully treated by surgery alone, which may therefore be sufficient treatment in immunocompetent subjects.

Pseudallescheria/Scedosporium complex species: From saprobic to pathogenic fungus

Scedosporiosis is an emerging fungal infection caused by Pseudallescheria/Scedosporium complex species (PSC). This pathogen has been drawn significant interest in recent years due to its worldwide prevalence, the seriousness of its infection, associated with high mortality in both immunocompromised and immunocompetent hosts and its cryptic ecology, distribution and epidemiology across the globe. These species complexes can be found in environments impacted by human. The purpose of this review is to describe the characteristics, mode of transmission, ecology, prevalence, global epidemiology of this fungal group in order to increase the awareness of among clinicians and microbiologists, especially in regions with high endemic, as well as to promote further research on all of its aspects.

Lamisil, a potent alternative antifungal drug for otomycosis

Background and Purpose:

Otomycosis is an acute, subacute or chronic fungal infection of the pinna, the external auditory meatus and the ear canal caused mainly by several species of saprophytic fungi. Lamisil (Terbinafine) is an allylamine antifungal agent, that is used both in the topical and oral administration for the treatment of dermatophytosis, cutaneous candidiasis, and the pityriasis versicolor. We investigated the in vitro activity of clotrimazole, miconazole, nystatin, and Lamisil against the agents of otomycosis.

Materials and Methods:

Fifteen clinically obtained isolates from otomycosis (Aspergillus species; n=13, and Candida species, n=2) and 8 environmental isolates of Aspergillus were tested. The disk diffusion method was employed to detect susceptibility. In the present study, the in vitro activity of the terbinafine with clotrimazole, miconazole, and nystatin against several isolates of Aspergillus and Candida with different sources were compared.

Results:

Out of 23 isolates of Aspergillus, Candida 4(17.4%) and 1(4.4%) were resistant to nystatin and miconazole, respectively. In addition, all tested organisms were sensitive to clotrimazole and terbinafine. Statistical analysis has shown that there are no significant differences on the effects of clotrimazole, miconazole and, terbinafine on saprophytic (environmental) and pathogenic isolates of A. niger, A. flavus, and A. terreus (P value= 0.85). In addition, all tested organisms were found to be highly susceptible to terbinafine (P< 0.04).

Conclusion:

This is a new approach for the possible use of Lamisil for the treatment of otomycosis.

ESCMID and ECMM joint guidelines on diagnosis and management of hyalohyphomycosis: Fusarium spp., Scedosporium spp. and others

Mycoses summarized in the hyalohyphomycosis group are heterogeneous, defined by the presence of hyaline (non-dematiaceous) hyphae. The number of organisms implicated in hyalohyphomycosis is increasing and the most clinically important species belong to the genera Fusarium, Scedosporium, Acremonium, Scopulariopsis, Purpureocillium and Paecilomyces. Severely immunocompromised patients are particularly vulnerable to infection, and clinical manifestations range from colonization to chronic localized lesions to acute invasive and/or disseminated diseases. Diagnosis usually requires isolation and identification of the infecting pathogen. A poor prognosis is associated with fusariosis and early therapy of localized disease is important to prevent progression to a more aggressive or disseminated infection. Therapy should include voriconazole and surgical debridement where possible or posaconazole as salvage treatment. Voriconazole represents the first-line treatment of infections due to members of the genus Scedosporium. For Acremonium spp., Scopulariopsis spp., Purpureocillium spp. and Paecilomyces spp. the optimal antifungal treatment has not been established. Management usually consists of surgery and antifungal treatment, depending on the clinical presentation.

Otomycosis: a retrospective study

Otomycosis is a fungal infection of the external ear canal with only a few studies about its real frequence in Brazil.

Aim

to evaluate otomycosis frequence and characteristics in patients with clinical suspicion of external otitis.

Study design

Retrospective study with transversal cohort (2000-2006).

Materials and methods

103 patients were assigned to mycological diagnosis (direct microscopic examination and culture).

Results

Otomycosis was diagnosed in 19.4% of the patients. Patient age varied from 2 to 66 years (an average of 23.5 years of age), and 60% of otomycosis cases were seen in women between 2 to 20 years of age. Chronic otitis, previous antibiotic therapy and the lack of cerumen were predisposing factors; itching, otalgia, otorrhea and hypoacusis were the symptoms reported by the patients. The most frequently isolated species were C. albicans (30%), C. parapsilosis (20%), A. niger (20%), A. flavus (10%), A. fumigatus (5%), C. tropicalis (5%), Trichosporon asahii (5%) and Scedosporium apiospermum (5%).

Conclusions

Otomycosis is endemic in JoÆo Pessoa-PB. Clinical exam and mycological studies are important for diagnostic purposes because otomycosis symptoms are not specific.