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Causative Agents of Fungal Keratitis in Northeastern Iran: A 3-Year Tertiary Care Hospital Study
Shaghayegh Moghadam1, Hossein Zarrinfar2,3, Ali Naseri4
1Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran.
Abstract:
Infectious keratitis is a significant ocular disease that, if left untreated, can lead to blindness. Fungi are among the causative agents that can result in severe symptoms. Keratitis infections are prevalent globally, with a higher incidence reported in tropical and subtropical regions. The current research focused on the molecular diagnosis of fungal keratitis and its prevalence over a 3-year period in northeastern Iran. The study involved the collection of 38 corneal scraping specimens from the Eye Specialized Hospital of Khatam in Mashhad, northeastern Iran. These specimens were cultured on Sabouraud dextrose agar, and the isolates were identified using DNA-based techniques. Among the patients studied (n = 38), 22 (58%) cases were caused by Aspergillus species (A. flavus, n = 17, A. fumigatus, n = 3; A. terreus, n = 1; A. tubingensis, n = 1), seven (18%) by Neocosmospora species (N. falciformis, n = 4; N. solani, n = 3), three (7%) by Candida albicans, two (5%) by Fusarium annulatum, and one case each (2%) by Penicillium chrysogenum, Cladosporium cladosporioides, and Cytospora sp. In addition, one case had a combined infection of A. flavus and P. glabrum. The results indicate a higher incidence of fungal keratitis in males, particularly in the age range of 40-60 years. Aspergillus sp., and specifically A. flavus, had the highest prevalence. Cladosporium cladosporioides is reported for the first time in this area as causal agent of keratitis. Additionally, this is the first report of keratitis likely caused by Cytospora species.
Insights
This study investigated fungal keratitis in northeastern Iran, finding Aspergillus species, particularly A. flavus, as the most common cause. New fungal agents for keratitis were identified in the region.
Area of Science:
- Ophthalmology
- Medical Mycology
- Molecular Diagnostics
Background:
- Infectious keratitis is a leading cause of blindness globally, with fungal infections posing severe risks.
- Tropical and subtropical regions exhibit higher incidences of keratitis.
- Molecular diagnostics are crucial for accurate identification of fungal pathogens in ocular infections.
Purpose of the Study:
- To determine the prevalence and molecular characteristics of fungal keratitis in northeastern Iran.
- To identify the specific fungal species responsible for infectious keratitis in the studied population.
- To report novel fungal agents causing keratitis in the region.
Main Methods:
- Collection of 38 corneal scraping specimens from patients with suspected keratitis.
- Culturing of isolates on Sabouraud dextrose agar.
- Molecular identification of fungal species using DNA-based techniques.
Main Results:
- Aspergillus species were the most prevalent (58%), with Aspergillus flavus being the most frequent isolate (n=17).
- Neocosmospora species accounted for 18% of infections.
- Cladosporium cladosporioides and Cytospora sp. were identified as new causative agents of keratitis in this region.
Conclusions:
- Aspergillus species, particularly A. flavus, are the primary cause of fungal keratitis in northeastern Iran.
- The study identified novel fungal pathogens, Cladosporium cladosporioides and Cytospora sp., contributing to keratitis.
- Fungal keratitis showed a higher incidence in males aged 40-60 years in this cohort.
