Microbial Keratitis in Nepal: Predicting the Microbial Aetiology from Clinical Features
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Date
2022
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Fungi
Abstract
Fungal corneal infection (keratitis) is a common clinical problem in South Asia. However,
it is often challenging to distinguish this from other aetiologies, such as bacteria or acanthamoeba.
In this prospective study, we investigated clinical and epidemiological features that can predict the
microbial aetiology of microbial keratitis in Nepal. We recruited patients presenting with keratitis to
a tertiary eye hospital in lowland eastern Nepal between June 2019 and November 2020. A structured
assessment, including demographics, history, and clinical signs, was carried out. The aetiology
was investigated with in vivo confocal microscopy and corneal scrape for microscopy and culture.
A predictor score was developed using odds ratios calculated to predict aetiology from features.
A fungal cause was identified in 482/642 (75.1%) of cases, which increased to 532/642 (82.9%) when
including mixed infections. Unusually, dematiaceous fungi accounted for half of the culture-positive
cases (50.6%). Serrated infiltrate margins, patent nasolacrimal duct, raised corneal slough, and
organic trauma were independently associated with fungal keratitis (p < 0.01). These four features
were combined in a predictor score. The probability of fungal keratitis was 30.1% if one feature
was present, increasing to 96.3% if all four were present. Whilst microbiological diagnosis is the
“gold standard” to determine the aetiology of an infection, certain clinical signs can help direct the
clinician to find a presumptive infectious cause, allowing appropriate treatment to be started without
delay. Additionally, this study identified dematiaceous fungi, specifically Curvularia spp., as the main
causative agent for fungal keratitis in this region. This novel finding warrants further research to
understand potential implications and any trends over time.
Description
Keywords
Microbial keratitis, Fungal keratitis, Dematiaceous fungi, Clinical diagnosis, Microbiology, Nepal, Curvularia spp, Fusarium spp
Citation
Hoffman, J.J.; Yadav, R.; Sanyam, S.D.; Chaudhary, P.; Roshan, A.; Singh, S.K.; Arunga, S.; Hu, V.H.; Macleod, D.; Leck, A.; et al. Microbial Keratitis in Nepal: Predicting the Microbial Aetiology from Clinical Features. J. Fungi 2022, 8, 201. https://doi.org/10.3390/jof8020201