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 Table of Contents  
Year : 2023  |  Volume : 3  |  Issue : 1  |  Page : 61-62

Neoscytalidium dimidiatum keratitis

1 Department of Ophthalmology, Khatib Eye Clinic, Mumbai, Maharashtra, India
2 Department of Microbiology, Saifee Hospital, Mumbai, Maharashtra, India

Date of Submission06-Jun-2022
Date of Acceptance26-Aug-2022
Date of Web Publication20-Jan-2023

Correspondence Address:
Zelda Vispi Dadachanji
6, Unity House, 3rd Floor, Bora Masjid Lane, Fort, Mumbai - 400 001, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijo.IJO_1374_22

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Keratomycoses are destructive, difficult-to-treat eye infections. A plant mold, Neoscytalidium dimidiatum, is an extremely rare cause of keratitis in humans. Direct microscopic examination and culture are essential for an early specific diagnosis and must be taken into consideration to establish the most effective treatment and avoid severe complications. Herein, we present a case of the first successfully treated case of N. dimidiatum keratitis in western India. Through this report, we wish to increase the awareness of this fungal species as a potential cause of keratitis and to provide the clinical, morphological, and microbiological features that might help in its treatment.

Keywords: Corneal ulcer, fungal keratitis, Neoscytalidium dimidiatum

How to cite this article:
Dadachanji ZV, Madhu GS, Khatib ZI, Khatib IZ. Neoscytalidium dimidiatum keratitis. Indian J Ophthalmol Case Rep 2023;3:61-2

How to cite this URL:
Dadachanji ZV, Madhu GS, Khatib ZI, Khatib IZ. Neoscytalidium dimidiatum keratitis. Indian J Ophthalmol Case Rep [serial online] 2023 [cited 2023 Feb 1];3:61-2. Available from: https://www.ijoreports.in/text.asp?2023/3/1/61/368137

Mycotic ulcers comprise a significant part of culture-proven keratitis in India (39%)[1] due to the tropical climate and large agrarian population, with Aspergillus and Fusarium being the most commonly isolated species.[1],[2] A plant mold, Neoscytalidium dimidiatum, known to cause skin and nail infections in humans, has extremely rare reports of ocular involvement.[3] Our case report demonstrates the first successfully treated case of N. dimidiatum keratitis in western India.

  Case Report Top

A 46-year-old male presented with complaints of redness, pain, and blurred vision in the left eye (LE) for the past 3 days. He gave history of soil from a construction site entering his LE, following which he rubbed his eye vigorously. He then self-administered moxifloxacin/dexamethasone eyedrops six hourly over 3 days in his LE before presenting to our clinic. He had no known systemic conditions. On examination, best-corrected visual acuity (BCVA) in LE was 20/200. LE cornea revealed an ulcer in the superotemporal quadrant, measuring 2 × 1 mm, with feathery extensions into the stroma. Anterior chamber was quiet and the lens was clear. Dilated fundus examination was normal. A presumptive diagnosis of mycotic keratitis was made, and patient was started on hourly topical natamycin 5%, topical moxifloxacin 0.5%, and homatropine eyedrops.

When the patient was reviewed in 48 h, his symptoms and infiltrates had worsened. The ulcer was central and measured 5 × 5 mm with 6 × 6 mm full-thickness stromal infiltrates. LE BCVA reduced to 20/2000. Ten percent potassium hydroxide wet preparation of the corneal scraping revealed the presence of abundant septate, branched hyphae [Figure 1]a. Gram's smear was negative for bacteria. The specimen was also cultured for bacteria, fungi, and Acanthamoeba. No bacterial growth was observed on blood agar within 24 h. The specimen inoculated in Sabouraud dextrose agar (SDA) plates showed no growth for the next 14 days. Topical 1% voriconazole eyedrops was added to the existing regimen. Routine blood tests were all within normal limits. Human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg), and hepatitis C virus (HCV) serologies were negative.
Figure 1: (a) KOH wet mount showing septate, branched hyphae. (b) Lactophenol blue mount shows cylindrical-shaped arthroconidia arranged in chains of one or two cells. (c) Effuse, dark gray to blackish-brown, hairy growth of Neoscytalidium dimidiatum on SDA plate. (d) Reverse of the SDA plate showing deep ochraceous-yellow growth. KPH = potassium hydroxide, SDA = Sabouraud dextrose agar

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A week later, the patient developed a 1-mm hypopyon with copious discharge [Figure 2]a. There was no further enlargement in the size of the ulcer. Patient was started on oral ketoconazole 200 mg twice daily and oral acetazolamide. B-scan ultrasonography was normal. Despite the above, the hypopyon showed no resolution over the next few days and an anterior chamber wash was done with intracameral and intrastromal injection of 50 μg/0.1 ml voriconazole. Following this, the hypopyon showed complete resolution and did not return over the course of the treatment. The stromal infiltrates, however, persisted. Therapeutic scraping was done at every visit.
Figure 2: (a) Central corneal ulcer measuring 5 × 5 mm with 6 × 6 mm full-thickness stromal infiltrates and 1-mm hypopyon with copious discharge (10 days after presentation). (b) Five months from the day of presentation, the LE shows a central macular opacity which is fading. LE = left eye

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Sixteen days after inoculation, the SDA plates showed growth. Lactophenol cotton blue mount showed cylindrical-shaped arthroconidia arranged in chains of one or two cells [Figure 1]b. SDA plates showed effuse, dark grey to blackish- brown hairy growth with deep ochraceous - yellow reverse [Figure 1]c and [Figure 1]d. The fungus was identified as N. dimidiatum based on the colonial and microscopic features.[4] We did a literature search and started the patient on hourly topical amphotericin-B 0.15%, topical fluconazole 0.3% eyedrops, and tablet itraconazole 200 mg daily. The infiltrates resolved gradually and the patient was weaned off all antifungal medications over the next 3 weeks.

At the time of writing this case report, 5 months from the day of presentation, the LE showed a central macular opacity 5 × 5 mm with unaided vision 20/120 [Figure 2]b.

  Discussion Top

Only a handful of reports of N. dimidiatum keratitis have been documented in literature. Two such cases reported from India[3],[5] had morphological features similar to our patient, but the patients were lost to follow-up. Another case of keratitis caused by Nattrassia mangiferae, a synanamorph of N. dimidiatum, was also reported as being lost to follow-up.[6] There is a well-documented case of N. dimidiatum keratitis from the USA, which was successfully treated with topical amphotericin-B and oral fluconazole.[7] In a recent case series from southeastern India, two out of three patients showed resolution of keratitis with topical natamycin and topical itraconazole, while one had to undergo therapeutic keratoplasty.[8]

In our patient, and other case reports,[3],[6],[8] trauma to the cornea, in otherwise healthy individuals, is observed. A corneal epithelial defect exacerbated by the patient rubbing his eye could have provided the portal of entry for the fungus present in the soil into the cornea. The early self-administration of topical steroids would have precluded clearance of the infection with normal immune defenses of the host.

Scytalidium species are typically fastidious and often require 2–3 weeks to grow in culture, which is best achieved on nonselective Sabouraud agar.[7] The primary isolation of this fungus from clinical specimens may be difficult as the isolates are sensitive to cycloheximide (actidione), which is commonly added to the primary isolation media used for culture.[4] Identification of the organism on culture and subsequent literature search revealed significant susceptibility to amphotericin-B[7],[9],[10] and additionally to fluconazole and itraconazole.[7],[9] This helped in timely modification of therapy, and we could avoid severe complications or even a therapeutic keratoplasty.

  Conclusion Top

To conclude, through our case report, we wish to raise awareness of N.dimidiatum as a potential cause of atypical, indolent fungal keratitis in India. Culture being the only means for diagnosing this infection, we emphasize the importance of good microbiological support for all ophthalmologists. Having a high index of suspicion and consistent communication with the microbiologist go a long way in ensuring optimal patient outcomes.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Chowdhary A, Singh K. Spectrum of fungal keratitis in North India. Cornea 2005;24:8-15.  Back to cited text no. 1
Prajna VN, Prajna L, Muthiah S. Fungal keratitis: The Aravind experience. Indian J Ophthalmol 2017;65:912-9.  Back to cited text no. 2
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Tendolkar U, Tayal RA, Baveja SM, Shinde C. Mycotic keratitis due to Neoscytalidium dimidiatum: A rare case. Community Acquir Infect 2015;2:142-4.  Back to cited text no. 3
  [Full text]  
Crous PW, Slippers MJ, Neoscytalidium dimidiatum (Penzig). In: Kidd S, Halliday C, Alexiou H, Ellis D, editors. Descriptions of Medical Fungi, Australia: Adelaide. 3rd ed. 2016. p. 141-3.  Back to cited text no. 4
Dharmshale S, Shinde D, Bali A, Kandle S. A rare fungal isolate Neoscytalidium dimidiatum from keratitis in a people living with HIV. World J Public Health Epidemiol 2022;1:1-4.  Back to cited text no. 5
Kindo AJ, Anita S, Kalpana S. Nattrassia mangiferae causing fungal keratitis. Indian J Med Microbiol 2010;28:178-81.  Back to cited text no. 6
[PUBMED]  [Full text]  
Farjo QA, Farjo RS, Farjo AA. Scytalidium keratitis: Case report in a human eye. Cornea 2006;25:1231-3.  Back to cited text no. 7
Mandlik K, Ramakrishnan S, Kabra N, Bhattacharya D, Gubert J. Mycotic keratitis due to rare fungal species Neoscytalidium: A case series. Indian J Ophthalmol Case Rep 2022;2:667-9.  Back to cited text no. 8
  [Full text]  
Sigler L, Summerbell RC, Poole L, Wieden M, Sutton DA, Rinaldi MG, et al. Invasive Nattrassia mangiferae infections: Case report, literature review, and therapeutic and taxonomic appraisal. J Clin Microbiol 1997;35:433-40.  Back to cited text no. 9
Madrid H, Ruíz-Cendoya M, Cano J, Stchigel A, Orofino R, Guarro J. Genotyping and in vitro antifungal susceptibility of Neoscytalidium dimidiatum isolates from different origins. Int J Antimicrob Agents 2009;34:351-4.  Back to cited text no. 10


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