|Year : 2015 | Volume
| Issue : 3 | Page : 462-463
Fungal keratitis in north India; Spectrum and diagnosis by Calcofluor white stain
MK Gupta1, A Chandra2, P Prakash1, T Banerjee1, OPS Maurya2, R Tilak1
1 Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
2 Department of Ophthalmology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
|Date of Submission||23-May-2014|
|Date of Acceptance||21-Jun-2014|
|Date of Web Publication||12-Jun-2015|
Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Gupta M K, Chandra A, Prakash P, Banerjee T, Maurya O, Tilak R. Fungal keratitis in north India; Spectrum and diagnosis by Calcofluor white stain. Indian J Med Microbiol 2015;33:462-3
|How to cite this URL:|
Gupta M K, Chandra A, Prakash P, Banerjee T, Maurya O, Tilak R. Fungal keratitis in north India; Spectrum and diagnosis by Calcofluor white stain. Indian J Med Microbiol [serial online] 2015 [cited 2020 Jul 4];33:462-3. Available from: http://www.ijmm.org/text.asp?2015/33/3/462/158609
Fungal corneal ulcer is a major cause of mono-ocular blindness in India, with filamentous fungi being responsible for the majority.  Prompt diagnosis is very much required for preservation of vision. Different methods have been used for diagnosis including Gram's stain, potassium hydroxide (KOH) wet mount, Calcofluor white fluorescent staining (CFW) and culture. This prospective study was undertaken to evaluate different fungal species responsible for corneal ulcer and compare the above diagnostic tests for identification.
A total of 119 suspected fungal corneal ulcer patients (history of recent ocular trauma with ulcerated lesion with feathery borders, satellite bodies surrounded by a ring of Wessely) were studied for 2 years. Corneal scrapings were collected and microscopic examination by above methods was done along with inoculation on Sabourauds Dextrose Agar and Blood agar in C-shaped pattern. Significant growth occurring along the C-shaped streak lines were identified by lactophenol cotton blue mount and slide culture.
A total 115 cases were positive for fungal elements by any one of the four diagnostic methods. Gram's stain, KOH mount, CFW with KOH and culture revealed positivity in 22.6%, 48.7%, 99.1% and 61.35% cases, respectively [Table 1]. On culture, hyaline fungi (51, 69.86%) had preponderance over phaeoid fungi. Aspergillus spp. (33, 45.2%) was most common followed by Fusarium spp. (11, 15.06%) and Curvularia spp. (9, 12.32%). Agriculturists (50, 42.01%) aged between 20-50 years were most frequently affected due to trauma by vegetative materials and sand particles (73.94%). Prior instillation of corticosteroids (24, 20.86%) and antibiotics (69, 60%) were observed.
|Table 1: Positive predictive value of different diagnostic methods in suspected fungal keratitis |
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Hyaline fungi, with Aspergillus spp from northern and eastern India and Fusarium spp. from south India, have been reported as the commonest cause of fungal keratitis. ,,, As emphasized previously, though culture is the most definitive method and direct visualization by KOH is most frequently used, a large number of cases that are missed can be easily detected by CFW stain with 10% KOH.
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