Related Experiment Video
Updated: Aug 28, 2025
Whole Genome Sequencing of Candida glabrata for Detection of Markers of Antifungal Drug Resistance
Published on: December 28, 2017
Otomycosis: The foremost aetiological agent causing otitis externa and the antifungal susceptibility pattern in
Behrad Roohi1,2, Shadman Nemati3, Abbas Alipour4
1Communicable Diseases Institute, Invasive Fungi Research Center, Mazandaran University of Medical Sciences, Sari, 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.
Insights
Otomycosis, a common fungal ear infection, is prevalent in north-western Iran, with Aspergillus species being the main cause. Antifungal drug resistance is emerging, particularly against triazoles.
Area of Science:
- Medical Mycology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Otomycosis is a recurring fungal infection of the ear.
- The external auditory canal offers an ideal environment for fungal proliferation.
Purpose of the Study:
- To identify fungal agents causing otomycosis in north-western Iran.
- To determine antifungal drug susceptibility patterns of these agents.
Main Methods:
- Cultured ear discharge and debris from 200 patients with otitis externa.
- Identified fungal agents using PCR-RFLP and sequencing.
- Assessed in vitro antifungal susceptibility via CLSI broth microdilution.
Main Results:
- Otomycosis prevalence was 50.5%, with Aspergillus section Nigri (58.57%) as the most common isolate.
- Aspergillus isolates showed low sensitivity to tioconazole and nystatin.
- Candida species had higher MICs against nystatin; Aspergillus isolates neared ECVs for itraconazole.
Conclusions:
- Otomycosis incidence is increasing, becoming a leading cause of otitis externa.
- Emerging resistance of Aspergillus to triazoles necessitates monitoring and potential treatment strategy adjustments.
Related Concept Videos
01:23Skin Diseases and Disorders
Gram-positive Staphylococcus spp. and Streptococcus spp. are responsible for many of the most common skin infections. However, many...
01:28Fungal Phylum Microsporidia
01:29Fungal Group Zygomycota
01:28Antimicrobial Effectiveness
01:28Fungal Phylum Ascomycota