|Year : 2016 | Volume
| Issue : 2 | Page : 89-91
Postoperative fungal endophthalmitis due to Basidiobolus ranarum: Report of a rare case
Radha Annamalai1, Anupma Jyoti Kindo2, Muthukumar Muthayya3
1 Department of Ophthalmology, Sri Ramachandra University, Porur, Chennai, India
2 Department of Microbiology, Sri Ramachandra Medical College and Research Institute, Porur, Chennai, Tamil Nadu, India
3 Professor, Department of Ophthalmology, Sri Ramachandra University, Porur, Chennai, India
|Date of Submission||22-Aug-2014|
|Date of Acceptance||26-Feb-2015|
|Date of Web Publication||9-Jun-2016|
Department of Ophthalmology, Sri Ramachandra University, Porur, Chennai - 600 116, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Postoperative fungal endophthalmitis is a significant cause of visual loss due to the rapid progress and severe inflammation. Management is dictated by the precise identification of fungus subspecies, choice of antifungal agent, and associated systemic features. We report a rare case caused by Basidiobolusranarum, never known to have caused endophthalmitis or any form of ocular infection or inflammation. A 59-year-old, Asian, immunocompetent, agriculturist presented with endophthalmitis on the 3 rd postoperative day. Smear and culture from the aqueous and vitreous samples detected a species of fungus called Basidiobolusranarum. Fungal endophthalmitis should be suspected even in patients who present in the early postoperative period and rare species considered even in immunocompetent individuals. Early detection and aggressive treatment is necessary for preventing morbidity or mortality due to these infections.
Keywords: Basidiobolusranarum, culture, fungus, intravitreal injection, postoperative endophthalmitis
|How to cite this article:|
Annamalai R, Kindo AJ, Muthayya M. Postoperative fungal endophthalmitis due to Basidiobolus ranarum: Report of a rare case. J Clin Ophthalmol Res 2016;4:89-91
|How to cite this URL:|
Annamalai R, Kindo AJ, Muthayya M. Postoperative fungal endophthalmitis due to Basidiobolus ranarum: Report of a rare case. J Clin Ophthalmol Res [serial online] 2016 [cited 2021 Mar 7];4:89-91. Available from: https://www.jcor.in/text.asp?2016/4/2/89/183719
Postoperative fungal endophthalmitis is relatively rare, but can be less responsive to treatment and result in poorer visual outcomes. The etiology can be exogenous or endogenous depending on the type of infection and has been reported to occur after asthma and intravitreal injections. , Yeast such as Candida albicans and filamentous fungi such as Aspergillus species and Fusariumsolani are the most frequent. The severity of clinical signs depends on the virulence of the fungus, extent of intraocular involvement and the immunity of the host. An aggressive approach with broad spectrum systemic antifungal with or without intravitreal injections or an immediate vitrectomy is required due to the violent inflammation. We report a case of postoperative fungal endophthalmitis, where a rare fungus was isolated after smear and culture of aqueous and vitreous samples.
| Case Report|| |
A 59-year-old man, agriculturist by occupation, presented to the outpatient department with complaints of pain and defective vision in his left eye. Phacoemulsification was performed on his left eye, at a local clinic, 3 days prior to his visit to our hospital. The surgery had been uneventful and he was a healthy immunocompetent man with no past history of any medical illness. All preoperative notes were found to be normal. Records of examination on the first postoperative day, showed that the wound was healthy, cornea clear, anterior chamber cells grade 1 and flare 1 +, posterior chamber intraocular lens was in situ, media clear, and fundus normal. His best corrected vision after the cataract surgery was 6/9 and N8. Slit lamp examination of the left eye on the 3 rd postoperative day revealed lid edema, corneal edema, hypopyon of 2 mm, anterior chamber cells of 4 +, and flare grade 4 [Figure 1]. Fundus was not visualized due to hazy media. His visual acuity was hand movements and near vision was less than N 36. B scan shows hyperechogenic shadows in the vitreous cavity and choroidal thickening and an attached retina [Figure 2]. His fasting blood sugar and examination of the right eye was normal. There were no lesions or wounds in any other part of the body to justify a source of infection.
|Figure 1: Slit lamp photograph of the anterior segment showing inflammation|
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|Figure 2: B scan shows hyperechogenic shadows in the vitreous cavity suggestive of vitreous infiltration and endophthalmitis|
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Samples of aqueous and vitreous were sent for analysis by smear and culture for bacteria and fungus following anterior chamber tap and vitreous aspiration. Smears revealed the presence of fungus and culture detected the fungus belonging to species Basidiobolusranarum based on its colony and microscopic features [Figure 3] and [Figure 4]. The B. ranarum isolate showed moderately fast growth at 30°C on Sabouraud's dextrose agar, with a diameter of 37 mm of spreading growth in 4 days. The colony was rugose and smooth, appearing greyish on the surface, a waxy texture with a pale reverse. After a week, formation of many satellite colonies was observed due to forced ejection of sporangioles (ballistospores). Microscopically, the hyphae were broad and aseptate. The isolate also produced a large number of asexual spores, some of which were characterized by the presence of a hyphal tag and some of which were characterized by cleavage formation to produce meristospores. The isolate also produced a large number of smooth-walled zygospores (18-46 μm) and some showing conjugation beaks, a characteristic feature of B. ranarum.
|Figure 3: The culture of Basidiobolusranarum on Sabouraud's dextrose agar showing brownish growth which are radially folded|
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|Figure 4: Lactophenol cotton blue mount shows the presence of large vegetative hyphae forming numerous round smooth-walled zygospores and some of them have a protrusion called the beaks (magnification, 215;40)|
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Polymerase chain reaction (PCR) was performed on the blood sample and the isolate was identified as belonging to the species B. ranarum. Confirmation of the isolate was done by gene sequencing. The internal transcribed region (ITS) was amplified and sequenced using ABI PRISM 3100 Genetic Analyzer (Applied Biosystems, USA). The sequence was then used for a nucleotide-nucleotide search using the Basic Local Alignment Search Tool (BLAST) algorithm at the National Center for Biotechnology Information (NCBI) website. The BLAST hits more than 98% were considered. The identity was with B. ranarum.
The patient was started on tablet voriconazole 200 mg twice daily after complete blood counts and liver function tests. The hypopyon and anterior chamber reaction remained the same. Intravitreal injection of amphotericin B in the dose of 5 μg in 0.1 ml was given as the patient refused surgery. Resolution of anterior chamber inflammation and vitritis was noted on clinical examination and B scan ultrasonography. His vision after 1 week was hand movements and N36, but improved to 6/60 after 3 weeks of antifungal treatment. The patient, however, was lost to follow-up and further evaluation was not possible.
| Discussion|| |
Fungal endophthalmitis is not as common as bacterial endophthalmitis, but it can be catastrophic to the eye as it progresses rapidly and causes severe complications. Besides, the narrow antifungal spectrum available makes our choice of treatment more difficult. Fungi usually cause delayed postoperative endophthalmitis. In tropical regions of the world, postoperative mold endophthalmitis is more common, may present more acutely, and Aspergillus is the major etiology.  Aspergillus species endophthalmitis after cataract surgery with implantation of preloaded intraocular lens  has been reported. Fungal endophthalmitis may have a similar presentation to bacterial endophthalmitis; and when the onset is in the early postoperative period, distinguishing between the two becomes difficult as occurred in our patient. PCR to detect fungus from intraocular specimens may not always be possible in certain populations due to economic constraints. Culture of intraocular fluids for both bacteria and fungus is the main diagnostic modality in such situations. PCR  and DNA-based molecular typing techniques show enormous potential for rapidly and accurately identifying the etiological agents of fungi.
Zygomycosis due to Basidiobolusranarum (entomophthoromycosisbasidiobolae, subcutaneous zygomycosis, subcutaneous phycomycosis, and basidiobolomycosis) is a granulomatous infection of the skin and subcutaneous tissues characterized by the formation of fluctuant firm and nontender swellings, generally on the extremities and trunk and rarely other parts of the body.  Systemic infection is rare. Basidiobolusis a true pathogen, causing infections in immunocompetent host. However, recent data on angioinvasive infections due to Basidiobolusin immunocompromised patients suggest that it is emerging as an opportunistic pathogen as well. The causative agent is common in soil, decaying vegetable matter, and the gastrointestinal tracts of amphibians, reptiles, fish, and bats.  It is presumed that infection is acquired through exposure to B. ranarum following minor trauma to skin or insect bites. The disease usually occurs in children, less often in adolescents, and rarely in adults. Males are much more frequently affected than females.
Since this patient was immunocompetent, the probable source of infection was the conjunctival flora or irrigating solutions. Novel antifungal agents (azole antifungals and echinocandins) are being investigated and optimizing the pharmacodynamics (PD) of our current antifungal therapies through such strategies as continuous infusion of amphotericin B and dose escalation of echinocandins and liposomal formulations of amphotericin B have also been investigated with mixed results.  Early onset and diffuse presentation, which mimics bacterial endophthalmitis, stresses the importance of both bacterial and fungal cultures from intraocular fluids to reach a diagnosis apart from the clinical judgment.
The organism is not rare, only that it has never been reported from endophthlamitis. This fungus has been reported from soft tissue sites and from rhinocerebral sites. In the past, clinical isolates of Basidiobolus were classified as B. ranarum, B. meristosporus, and B. haptosporus; but recent taxonomic studies based on antigenic analysis, isoenzyme banding, and restriction enzyme analysis of rDNA indicate that all human pathogens belong to B. ranarum.
| Conclusion|| |
Corneal involvement was reported to be the most important predictor of outcome in cases of fungal endophthalmitis.  This case is being reported due to the isolation of a new species of fungus as a causative organism in a scenario that resembled bacterial endophthalmitis. This widens the already existing ambiguity with regard to the presentation of fungus. Failure to consider varied fungal etiologies even in a seeming clinical picture of bacterial endophthalmitis may delay precise diagnosis and appropriate management.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]