Southern Iran Infection Study
Molecular sequencing of 104 patient cases in southern Iran identified Aspergillus tubingensis and Aspergillus niger as the primary drivers of otomycosis between November 2018 and March 2019.
The cross-sectional study evaluated 104 individuals with confirmed external auditory canal infections. Researchers utilized molecular sequencing methods, applying $\beta$-tubulin sequencing for molds and ITS region sequencing for yeasts, to improve diagnostic accuracy over traditional microscopic observation alone.
Symptoms and Patient Demographics
Patients presented with distinct clinical manifestations, where itching affected 81.7% of the cohort. Inflammation was documented in 80% of cases, and otorrhea appeared in 74%.
Demographic analysis showed that 55% of the enrolled patients were female. Nearly half of the total study population fell within the 40 to 60 age bracket.
Antifungal Susceptibility Patterns
Laboratory cultures produced 102 mold isolates and 16 yeast isolates from the patient samples. Posaconazole and amphotericin B demonstrated potent in vitro activity against the majority of Aspergillus isolates, while fluconazole showed limited efficacy against molds.
Among the yeast isolates, three-quarters of the Candida specimens remained susceptible to fluconazole. Candida albicans and Candida parapsilosis emerged as the most frequent yeast species recovered in the testing.
Aspergillus species drive most infections
What caused most otomycosis cases in the study?
Sequencing confirmed Aspergillus tubingensis at 36.3% and Aspergillus niger at 28.4% as the main species responsible for the infections. Microscopic observation initially identified the A. niger complex as the predominant agent.
Which antifungal medications worked best in vitro?
Posaconazole and amphotericin B showed potent activity against most Aspergillus isolates tested during the microdilution methods. Conversely, fluconazole demonstrated limited efficacy against the mold isolates.
How were the fungal agents identified?
Researchers performed molecular identification using $\beta$-tubulin sequencing for molds and ITS region sequencing for yeasts. This approach improved species identification accuracy compared to standard microscopy.
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