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 ~  Abstract
 ~ Introduction
 ~ Case Report
 ~ Discussion
 ~ Conclusion
 ~  References
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  Table of Contents  
CASE REPORT
Year : 2020  |  Volume : 38  |  Issue : 3  |  Page : 475-477
 

A rare case of Colletotrichum truncatum keratitis in a young boy with complete healing after medical treatment


Department of Cornea and Refractive Services, Aravind Eye Hospital, Pondicherry, India

Date of Submission04-Apr-2020
Date of Decision26-May-2020
Date of Acceptance26-Jun-2020
Date of Web Publication4-Nov-2020

Correspondence Address:
Dr. Josephine S Christy
Aravind Eye Hospital, Cuddalore Road, Thavalakuppam - 605 007, Puducherry
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijmm.IJMM_20_146

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 ~ Abstract 


Colletotrichum is a rare fungal pathogen, which is known to cause anthracnose in plants and keratitis or subcutaneous infections in humans. Among the seven Colletotrichum species reported in eye infections, truncatum species is usually virulent with poor visual prognosis even after surgical treatment. Here we report a case of Colletotrichum truncatum keratitis in a young boy with thorn injury that completely resolved with topical natamycin and voriconazole.


Keywords: Colletotrichum trunctaum keratitis, therapy, C. capsicii


How to cite this article:
Christy JS, Balraj A, Agarwal A. A rare case of Colletotrichum truncatum keratitis in a young boy with complete healing after medical treatment. Indian J Med Microbiol 2020;38:475-7

How to cite this URL:
Christy JS, Balraj A, Agarwal A. A rare case of Colletotrichum truncatum keratitis in a young boy with complete healing after medical treatment. Indian J Med Microbiol [serial online] 2020 [cited 2020 Nov 24];38:475-7. Available from: https://www.ijmm.org/text.asp?2020/38/3/475/299815





 ~ Introduction Top


Colletotrichum species are coelomycetous soil fungi that are commonly found in tropical and subtropical countries. They usually enter human tissue by trauma with organic matter causing ocular or subcutaneous infections. There are seven species identified to cause keratitis.[1] Infections by Colletotrichum gloeosporioides, Colletotrichum dematium and Colletotrichum graminicola usually resolves by medical treatment.[1] Whereas, Colletotrichum truncatum is known to cause severe infection, progressing to endophthalmitis and requiring surgical intervention.[2] We report a unique case of C. truncatum (Colletotrichum capsicii) keratitis in a young boy following thorn injury which presented along with severe scleral inflammation masquerading like peripheral ulcerative keratitis (PUK) and finally resolved completely with medical treatment. Interestingly, C. capsicii is the most common plant pathogen endemic in this region of India.


 ~ Case Report Top


A 12-year-old young boy presented with history of pain and redness in the right eye for five days following thorn injury. The patient had used a drop of breast milk to the right eye which is a common native treatment practiced in rural south India. Presenting visual acuity was 6/12. Slit-lamp examination revealed 2 mm × 4 mm anterior stromal corneal infiltrate parallel to limbus along with stromal thinning and few satellite lesions. He underwent diagnostic scrapings for bacteria and fungi. Direct microscopic examination of the scraping with gram stain and 10% KOH showed no organism. The bacterial and fungal cultures were negative. Patient was initiated with treatment of topical Natamycin 5% eye drops (e/d) Hourly, Itraconazole 1% eye ointment twice a day and Gatifloxacin 0.3% e/d six times/day. After one week, there was increase in infiltrate size along with adjacent scleral inflammation and swelling. Scleral site exploration was done to rule out any foreign body which was negative [Figure 1]. In order to rule out PUK, immunology workup was done and found to be normal. At the end of three weeks, keratitis was nonhealing with aggressive scleral inflammation. Patient was started on low dose topical steroids and the response was good with complete healing of lesion in two weeks. Surprisingly, two weeks later, the lesion got reactivated with a new corneal infiltrate involving anterior half of the stromal bed with extension to paracentral part of the cornea [Figure 2]. Repeat scraping revealed fungal filaments in KOH and culture on Potato Dextrose agar grew moderate cottony colonies. The obverse started greyish and gradually darkened to black; the reverse was greyish-black with patchy sclerotia [Figure 3]. Lactophenol blue preparation of the slide-culture showed hyaline septate branched hyphae with few slightly irregular smooth appressoria. Conidia were long (20 μm) falcate or fusiform, nonseptate and tapered on each end [Figure 4]. Based on colony morphology and microscopy the fungus was tentatively identified as Colletotrichum spp. The isolate was confirmed as C. truncatum via sequencing of the internal spacer regions of ribosomal DNA, at AMRF Madurai, India. Topical steroids were withdrawn and patient was vigorously treated with hourly 5% Natamycin and 1% Voriconazole e/d. The lesion healed completely in three weeks with corneal scar [Figure 5]. The final best corrected visual acuity was 6/12. Patient was followed up for one year and there has been no recurrence of keratomycosis.
Figure 1: Peripheral corneal thinning and leading edge infiltrate with adjacent scleral inflammation (postscleral exploration)

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Figure 2: Active stromal infiltrate in the paracentral region with resolved primary lesion in periphery

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Figure 3: Potato dextrose agar showing growth of greyish black cottony colonies

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Figure 4: Lactophenol cotton blue mount of slide culture showing hyaline septate branched hyphae and fusiform, nonseptate conidia with tapered ends

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Figure 5: Healed paracentral corneal scar

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 ~ Discussion Top


The genus Colletotrichum is a typical plant pathogen which is included in order Melanconiales of Coelomycetous fungi because of formation of cup shaped conidiomata. Colletotrichum spp. are usually pathogenic on plants, in which they cause anthracnosis, necrosis, leaf spot, and fruit rot. In Tamil Nadu, C. capsicii is known to infect chilli fruit which in turn can cause C. truncatum keratitis.[1] Interestingly C. capsicii is the most common plant pathogen endemic in this region of India. Injury with vegetable matter remains the most common risk factor apart from steroid use, antiviral use and diabetes.[3] Our patient had history of thorn injury and primary presentation with keratitis and scleral inflammation masquerading as PUK. The second episode of keratitis while patient was on topical steroids grew the Colletotrichum fungus. Whether the use of breast milk by the patient had prevented the growth of fungus during the primary presentation remains speculative.

Colletotrichum is listed as the fifth most common cause of fungal keratitis.[4] The ulcers usually are central or paracentral in position with irregular or serrated edges and progress slowly compared to Aspergillus or Fusarium keratitis. Brown pigmentation may be noted in the ulcer bed as the fungus is a dematiaceous mold.[1] Clinical picture in our patient was initially as limbal infiltrate with associated thinning and conjunctival inflammation. This mimicked a PUK and posed us a diagnostic challenge. Though the investigations for autoimmune aetiology were negative, the prolonged nonhealing course steered us to use topical steroids. Probably, the young age of the patient and the limbal site of initial injury could have activated aggressive scleral inflammation that responded well to steroids. When the patient was on local immunosuppression without antifungals, the fungus reactivated and presented with an infiltrate adjacent to the original site in the paracentral region. Age of the patient presenting with Colletotrichum keratitis in previous reports have been from 18 to 80 years. This report is unique due to the unusual presentation in a young boy.

Most ocular infections due to Colletotrichum species respond to natamycin inspite of high minimum inhibitory concentration (MIC) byin vitro susceptibility tests.[3] Amphotericin B, clotrimazole and miconazole have found to have low MIC in various other studies.[2] A combination of natamycin and azole with a treatment period of 8–10 weeks is found to be effective for medical treatment.[5] Among the Colletotrichum species, C. truncatum is found to be virulent with complications like endophthalmitis. Literature search revealed five cases reported by Shivaprakash et al.[1] and one by Squissato et al.[2] Among these cases, four required therapeutic keratoplasty, three progressed to endophthalmitis and two ended as painful blind eyes. Late presentation and delay in initiation of treatment could be the reason for poor outcomes. Kaliamurthy et al.[3] has reported seven cases of Colletotrichum spp. keratitis from Tamil Nadu. Considering the endemic nature in this region, these could be truncatum species. Among the seven cases, five responded well to topical natamycin and two required therapeutic keratoplasty. The average duration of medical therapy for complete resolution ranged from two to six weeks. In our case, complete resolution was achieved with topical natamycin and voriconazole in four weeks.


 ~ Conclusion Top


Difficult morphological identification, prolonged indolent course of the disease and high degree of antifungal resistance can delay early diagnosis and initiation of appropriate treatment. This can lead to complications such as endophthalmitis and complete loss of vision.[4] Hence, although Colletotrichum infection in humans is rare, a high level of suspicion is essential especially in endemic regions. Prompt initiation of antifungals can attain good visual recovery.

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.

Acknowledgement

Joseph Gubert, Microbiologist.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
 ~ References Top

1.
Shivaprakash MR, Appannanavar SB, Dhaliwal M, Gupta A, Gupta S, Gupta A, et al. Colletotrichum truncatum: An unusual pathogen causing mycotic keratitis and endophthalmitis. J Clin Microbiol 2011;49:2894-8.  Back to cited text no. 1
    
2.
Squissato V, Yucel YH, Richardson SE, Alkhotani A, Wong DT, Nijhawan N, et al. Colletotrichum truncatum species complex: Treatment considerations and review of the literature for an unusual pathogen causing fungal keratitis and endophthalmitis. Med Mycol Case Rep 2015;9:1-6.  Back to cited text no. 2
    
3.
Kaliamurthy J, Kalavathy CM, Ramalingam MD, Prasanth DA, Jesudasan CA, Thomas PA. Keratitis due to a coelomycetous fungus: Case reports and review of the literature. Cornea 2004;23:3-12.  Back to cited text no. 3
    
4.
Pote ST, Chakraborty A, Lahiri KK, Patole MS, Deshmukh RA, Shah SR. Keratitis by a rare pathogen Colletotrichum gloeosporioides: A case report. J Mycol Med 2017;27:407-11.  Back to cited text no. 4
    
5.
Yegneswaran PP, Pai V, Bairy I, Bhandary S. Colletotrichum graminicola keratitis:First case report from India. Indian J Ophthalmol 2010;58:415-7.  Back to cited text no. 5
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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]



 

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