|Year : 2020 | Volume
| Issue : 1 | Page : 74-77
Ocular scedosporiosis in an immunocompetent host
Ashish Bajaj, Bibhabati Mishra, Archana Thakur, Poonam Sood Loomba, Abha Sharma
Department of Microbiology, Govind Ballabh Pant Institute of Postgraduate Medical Education and Research, Delhi, India
|Date of Submission||11-Aug-2019|
|Date of Decision||23-Sep-2019|
|Date of Acceptance||22-Nov-2019|
|Date of Web Publication||19-Jun-2020|
Department of Microbiology, Govind Ballabh Pant Institute of Postgraduate Medical Education and Research, Delhi
Source of Support: None, Conflict of Interest: None
Scedosporium apiospermum infection in humans is rare. Fungal keratitis is the most common manifestation of S. apiospermum infection in immunocompetent individuals. S. apiospermum is a filamentous fungus found in soil and polluted water. Strong suspicion of fungal keratitis should be made in all corneal ulcers with a history of trauma with vegetative matter or soil. Here, we present a case of fungal keratitis caused by S. apiospermum in an immunocompetent host.
Keywords: Fungal keratitis, keratomycosis, ocular scedosporiosis, Scedosporium apiospermum
|How to cite this article:|
Bajaj A, Mishra B, Thakur A, Loomba PS, Sharma A. Ocular scedosporiosis in an immunocompetent host. CHRISMED J Health Res 2020;7:74-7
|How to cite this URL:|
Bajaj A, Mishra B, Thakur A, Loomba PS, Sharma A. Ocular scedosporiosis in an immunocompetent host. CHRISMED J Health Res [serial online] 2020 [cited 2020 Sep 23];7:74-7. Available from: http://www.cjhr.org/text.asp?2020/7/1/74/286892
| Introduction|| |
Corneal opacification following various infections is the second major cause of blindness after cataract. Due to large agrarian population and environmental factors, keratomycosis is common in India. Majority of keratomycosis cases occur among agricultural workers following a corneal trauma by vegetative matter. The causative fungi responsible are ubiquitous organisms. Keratitis caused by Scedosporium apiospermum is rare and is often associated with trauma with organic or vegetative matter. Here, we report a case of keratomycosis caused by S. apiospermum.
| Case Report|| |
A 45-year-old male, resident of Noida, Uttar Pradesh, presented to a tertiary care hospital with complaints of swelling, excessive watering, redness, pain, and photophobia in the right eye for 3 days. He had a history of trauma to the right eye with soil material while traveling past an agriculture land. The pain and redness increased gradually. He admitted using rose water and honey in the eye before coming to the hospital. He had no past history of any chronic illness such as diabetes or hypertension. He had a history of road traffic accident 2 years back, which resulted in weakness of the right side of the body and facial palsy.
On examination, visual acuity in the right eye was 6/24 and left eye was 6/6. The affected eye revealed severe conjunctival congestion and corneal ulcer of 3 mm × 4 mm in size along with corneal infiltrates. Right eyelid gaping was also observed. The patient was initially treated in the outpatient department with local analgesics and antibiotics. Fungal infection was not considered as trauma was not by vegetative matter. The patient was asked to visit after 7 days.
On follow-up after 1 week, the disease progression was drastic as visual acuity in the right eye was limited to the perception of light (PL+). On further examination, the cornea was found to be fully opaque, and the patient was admitted. Ultrasound of the eye revealed no infiltrates in the vitreous humor [Figure 1]. The antibiotic therapy was continued, and therapeutic penetrating keratoplasty (TPK) was done on the 10th day of hospital admission. The infected cornea was removed and sent for microbiological analysis.
|Figure 1: Ultrasonographic image of the eye on day 1 showing no vitreous infiltrates|
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In the microbiology laboratory, the corneal tissue received was processed as per standard guidelines. Potassium hydroxide mount revealed the presence of acute-angled fungal hyphae. Gram stain of the specimen also revealed the presence of acute-angled branching fungal hyphae. Oral fluconazole twice daily and natamycin eye drops 4 hourly were added in the treatment. The corneal tissue was inoculated onto blood agar and chocolate agar plates along with a Sabouraud's dextrose agar (SDA) (HiMedia, Mumbai, Maharashtra, India) tube. It was also inoculated onto two sets of SDA plates. The plates were then incubated at 25°C and at 37°C.
After 7 days of incubation, on examining the SDA, fast-growing, cottony fluffy growth, suede-like downy colonies with a grayish-black reverse was observed [Figure 2]. Growth was also observed in SDA with cycloheximide.
Microscopically, lactophenol cotton blue preparation [Figure 3] and [Figure 4] showed septate hyphae with slender, short, and long conidiophores, bearing single, oval, or club-shaped, unicellular conidium. Based on cultural and microscopic morphology on SDA, the final diagnosis of S. apiospermum was made.
|Figure 4: Lactophenol cotton blue mount showing characteristic sperm-shaped single conidia|
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After 10 days, by the time the fungal culture growth was obtained and diagnosis of S. apiospermum was made, the graft implanted after TPK also got infected with infiltrates. Ultrasound of the eye showed infiltrates in the vitreous humor extending till the retina [Figure 5]. Despite the ongoing antifungal treatment, the condition of the eye worsened. As S. apiospermum is known to be notorious and resistant to commonly used antifungals along with high mortality, evisceration was done on the 29th day of hospital admission, in order to save the life of the patient. The patient was counseled and was explained the necessary details. The patient was discharged after 2 days. After 1 week of revisit, the wound was healthy. After that, the patient was lost to follow-up.
|Figure 5: Ultrasonographic image of the eye showing vitreous infiltrates|
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| Discussion|| |
S. apiospermum, asexual state (anamorph) of Pseudallescheria boydii, is an opportunist fungus with a high level of reported antifungal resistance. This is a filamentous fungus found in soil, polluted water, and manure. The disease spectrum ranges from transient colonization of the respiratory tract to allergic bronchopulmonary reaction, invasive localized disease, and severe disseminated disease.
Worldwide, there are increased reports of dematiaceous fungi causing keratitis, which account for 10%–15% of the total fungal keratitis cases. They are the third most frequently encountered fungi following Aspergillus and Fusarium. However, there are few reports on keratomycosis caused by S. apiospermum in the Indian subcontinent.,,,,
Among the ocular infections, keratomycosis is the most common manifestation of S. apiospermum in immunocompetent people, and mostly are preceded by a corneal injury due to some trauma. As documented, S. apiospermum keratitis is rare but may be the most common site of infection in immunocompetent patients.,
In our case, the patient was a 43-year-old male and a healthy, immunocompetent, and industrial worker by occupation. Various studies of keratomycosis caused by S. apiospermum in India are mentioned in [Table 1].
|Table 1: Studies of Keratomycosis due to Scedosporium apiospermum from the Indian subcontinent|
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A definitive diagnosis requires fungal culture which is also crucial for antifungal susceptibility. Both asexual and sexual states of these fungi could be obtained from corneal ulcers. Depending on the microscopic morphology, the diagnosis of Scedosporium, Graphium, or Pseudallescheria can be made. The physiological properties of Scedosporium have also been explored for use as a diagnostic tool to differentiate it from similar species such as Scedosporium prolificans. Scedosporium is usually recognized by its morphological features, but to facilitate its identification, several serological techniques have also been developed which can recognize pathogen even in tissues. These tests include cycloheximide tolerance test and assimilation of various sugars, nitrates, higher alcohol, and sugar acids. The other approaches for the diagnosis are serodiagnosis, counter immunoelectrophoresis, and polymerase chain reaction.
Scedosporium remains resistant to amphotericin B and flucytosine. Azoles remain as the drug of choice, with itraconazole used as the most common agent. Surgical resection of local lesion with adequate margins gives better results. Various studies,, used azoles for treatment and have achieved success.
There are reports, where topical antifungal treatment did not appear to be efficacious and enucleation was required to resolve Scedosporium ocular infections regardless of the causative species.
In the present case, the patient was treated with antibiotics for 17 days without suspecting fungal infection and then TPK was performed. On reporting of fungal hyphae from the sample received after TPK, antifungal treatment (fluconazole and natamycin) was started and continued for 12 days. However, the patient ended up having infiltrates in the vitreous humor, and the eye had to be eviscerated. A similar case of fungal panophthalmitis was described by Ksiazek et al. following S. apiospermum keratitis. The eye had to be ultimately eviscerated. The other eye had 6/6 vision throughout the hospital stay and up to 7 days of revisit after discharge. Scedosporium spp. are reported to cause deep-seated infections such as endophthalmitis which may disseminate to involve the central nervous system.
To conclude, S. apiospermum is a rare cause of fungal keratitis. The severity of infection can be contained by prompt antifungal treatment. Strong suspicion/provisional diagnosis of fungal keratitis should be made in all corneal ulcers with a history of trauma with vegetative matter or soil. Intraocular spread of infection almost always results with poor 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.
We are thankful to Dr. J. L. Goyal, Director Professor, and Dr. Gaurav Singh, 2nd year postgraduate student, Department of Ophthalmology, Guru Nanak Eye Centre, New Delhi, for providing the clinical sample.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]