Case Report: Poor Outcome Despite Aggressive Management in Pythium insidiosum Endophthalmitis.

Pythium insidiosum is a parasitic oomycete that can cause keratitis and closely resembles fungus, both clinically and morphologically. It requires a trained microbiologist for its differentiation from fungal filaments and has poor response to antifungal therapy. We present a case of primary isolation of the organism from the vitreous cavity in a case of endophthalmitis. The infection spread quickly and involved all the ocular tissues. The eye had poor visual outcome despite a sequence of rapidly completed retinal and corneal surgeries along with initiation of anti-Pythium therapy.

Linezolid shows high safety and efficacy in the treatment of Pythium insidiosum keratitis in a rabbit model.

Efficacy and safety of three antibiotics (Linezolid-LZ, 0.2%; Azithromycin-AZ, 1%; Tigecycline-TG, 1%) were determined in the treatment of Pythium insidiosum keratitis in rabbits. Infection of right eye of 38 rabbits was induced by standard intracorneal injection of P. insidiosum zoospores (left eye, intracorneal saline). Corneal infection developed in all right eyes. One hourly eye drops of one of the three antibiotics was instilled in both eyes (3 groups of 12 rabbits each) except in controls. Half of the rabbits in each group received intracorneal injection of the respective antibiotic after 4 days of starting eye drops. Clinical scoring of eyes was done over next 3 weeks. The reduction in scores post-treatment was significant for each drug (LZ: p < 0.025, AZ: p < 0.025, TG: p < 0.01). Scores with LZ (median change of 3) was significantly (p = 0.013) higher than TG (median change of 2) and comparable (p = 0.06) to AZ (median change of 3). Reduction in clinical scores in eyes receiving intracorneal antibiotics was not significantly different from the eyes that did not receive intracorneal antibiotics (p = 0.73). While no adverse effect of LZ was seen in the control corneas, 66-100% of rabbits showed reaction to AZ and TG. Histopathology showed severe inflammation in all infected corneas and intraocular extension in some of the rabbits with poor response. The success rate was noted to be 16.7%, 25% and 50% in AZ, TG and LZ respectively (p = 0.45). LZ demonstrated superior efficacy and safety and can be considered for trial in human disease.

Outcome of therapeutic deep anterior lamellar keratoplasty in advanced Acanthamoeba keratitis.

Purpose: To report and analyze the outcomes of therapeutic deep anterior lamellar keratoplasty (DALK) in patients with advanced Acanthamoeba keratitis (AK). Methods: Medical records of microbiologically confirmed AK, underwent DALK from 2004 to 2017, were reviewed and the data related to early and late outcome including complications were retrieved. Outcome of cases with largest diameter of infiltrate ≥8 mm at the time of surgery (advanced keratitis) were analyzed and compared with those with less severe keratitis (infiltrate size less than 8 mm). Results: Out of 23 patients of AK in whom DALK was performed, ten (43.4%) patients had advanced keratitis. Mean age of these patients was 38.7 ± 8.6 years (range, 25 to 56). Median visual acuity at presentation was 2.78 (IQR, 1.79-3.0) that improved to 1.79 (IQR, 0.70-2.78) postoperatively. Early complications included recurrence of AK in 2 (20%), Descemet's membrane detachment in 5 (50%), and persistent epithelial defect in 3 (30%) cases. Overall, 6 (60%) grafts failed, whereas 4 (40%) patients had clear graft at their last follow-up. Median follow-up of these cases was 5 months (IQR, 1.4-11.4). One graft developed stromal rejection, which resolved with increased dose of corticosteroids. In comparison, DALK performed for less severe keratitis (N = 13) had 1 (7.6%) recurrence and 2 (15.8%) grafts failure (OR, 8.25). The probability of one-year graft survival and eradication of infection was 32% and 74.1%, respectively, in advanced cases compared to 91.6% and 83.9% in less severe cases. Conclusion: Outcome of DALK in advanced Acanthamoeba keratitis is less favorable compared to those carried out for less severe keratitis cases.

Clinical and Histopathological Evaluation of a Rabbit Model for Pythium insidiosum Keratitis.

Purpose: To describe the clinical characteristics and histopathological features in a rabbit model of Pythium insidiosum keratitis.Methods: Zoospores of P. insidiosum isolated from a patient with microbial keratitis were used for inoculation of the right eye of 48 New Zealand White rabbits in either low (LD) or high dose (HD). Apart from variable dosage the rabbits were grouped (6 rabbits per group) based on route of inoculation (topical on abraded cornea or intracorneal) and immunosuppression (subconjunctival steroid or no steroid). Left eye received phosphate buffered saline via route similar to the right eye. Daily clinical examination of the eye was done, the corneas were harvested on day 3, 7 and 9 and part of the cornea was preserved in 10% neutral buffered formalin for histopathological examination.Results: Left eye of all rabbits were clinically normal. Eyes with intracorneal injection of zoospores developed infection irrespective of dose of inoculation and administration of steroids. One of the consistent early signs of infection was ring like infiltrate in the peripheral cornea. On day 2, rabbits receiving HD developed significantly greater inflammation compared to LD [median clinical score in HD- 11 (IQR = 10-12), versus 9 (IQR = 8-9) in LD (p = 0.004)]. The density of inflammation showed temporal correlation (increase with time) when the inoculum was low. Of the rabbits that received topical inoculation one rabbit cornea showed mild infiltrate in steroid group while no eye was infected in the group without steroid. Sparsely septate to aseptate branching filaments were noted in the stroma of all infected corneas.Conclusions: We describe the first animal model of Pythium keratitis that holds promise for future studies. While topical inoculation of zoospores was unsuccessful in causing infection intracorneal inoculation without immunosuppression was sufficient to develop clinically severe keratitis in rabbits.

Exserohilum keratitis: Clinical profile of nine patients and comparison of morphology versus ITS-Based DNA sequencing for species identification of the fungal isolates.

PURPOSE: The objective of this study was to describe the microbiological and clinical features of nine cases of Exserohilum keratitis. PATIENTS AND METHODS: Fungal isolates from corneal scrapings were identified based on macroscopic and microscopic characteristics of the colonies and DNA sequencing of ITS1-5.8S-ITS2 region in the rRNA gene. All patients were treated with topical and if required systemic antifungals. Therapeutic penetrating keratoplasty (TPK) was done in case of failed medical therapy. RESULTS: Morphologically, all fungal isolates were Exserohilum rostratum except one Exserohilum mcginnisii. Based on the BLAST analysis, 6 isolates showed 100% similarity to Setosphaeria rostrata (CBS 112815) and E. mcginnisii (CBS 20308). The other three isolates were Setosphaeria holmii (CBS 128053), not reported earlier in fungal keratitis. Three patients were lost to follow-up and response to medical therapy was good (Healed scar - 4 patients). Two out of nine patients were advised TPK. CONCLUSIONS: Diagnosis and clinical features of Exserohilum keratitis are akin to other dematiaceous keratitis. The two morphological species of E. mcginnisii and E. rostratum are indistinguishable from Setosphaeria rostratum at DNA sequence level, which justifies the retention of the latter nomenclature.

Non-contact lens related Acanthamoeba keratitis.

The purpose of the study is to describe epidemiology, clinical features, diagnosis, and treatment of Acanthamoeba keratitis (AK) with special focus on the disease in nonusers of contact lenses (CLs). This study was a perspective based on authors' experience and review of published literature. AK accounts for 2% of microbiology-proven cases of keratitis. Trauma and exposure to contaminated water are the main predisposing factors for the disease. Association with CLs is seen only in small fraction of cases. Contrary to classical description experience in India suggests that out of proportion pain, ring infiltrate, and radial keratoneuritis are seen in less than a third of cases. Majority of cases present with diffuse infiltrate, mimicking herpes simplex or fungal keratitis. The diagnosis can be confirmed by microscopic examination of corneal scraping material and culture on nonnutrient agar with an overlay of Escherichia coli. Confocal microscopy can help diagnosis in patients with deep infiltrate; however, experience with technique and interpretation of images influences its true value. Primary treatment of the infection is biguanides with or without diamidines. Most patients respond to medical treatment. Corticosteroids play an important role in the management and can be used when indicated after due consideration to established protocols. Surgery is rarely needed in patients where definitive management is initiated within 3 weeks of onset of symptoms. Lamellar keratoplasty has been shown to have good outcome in cases needing surgery. Since the clinical features of AK in nonusers of CL are different, it will be important for ophthalmologists to be aware of the scenario wherein to suspect this infection. Medical treatment is successful if the disease is diagnosed early and management is initiated soon.

Retinopathy of vivax malaria in adults and its relation with severity parameters.

Malarial retinopathy is a set of retinal signs in severe malaria due to falciparum malaria. With increased recognition of severe manifestations of vivax malaria, a systematic study to evaluate retinal changes in vivax malaria could elaborate our knowledge about this neglected entity. This observational study included retinal examination of 104 adult patients (>14 years) with varying severity of vivax malaria admitted to a tertiary care center during peak seasons of 2012 and 2013. Thirty-eight percent of severe cases had a retinal sign as compared to 6% of non-severe cases (p < 0.01). No statistically significant effect of residence or age on the presence of retinopathy was noted. Females were found to be more prone to develop a retinal sign (p < 0.01). Presence of retinal signs was significantly associated with anemia and jaundice. No statistical association was noted for retinal signs to be present in either renal dysfunction or altered thrombocytes count. The most common signs were arteriovenous changes, present in eight cases (19%) of severe malaria and three cases (5%) of non-severe malaria. Retinal hemorrhage was present in five cases (12%) of severe malaria and no case of non-severe malaria. Both superficial and deep hemorrhages were seen including white-centered hemorrhages. Other signs included cotton wool spots, hard exudates, blurred disk margins with spontaneous venous pulsations and bilateral disk edema. A correlation between retinal signs and severity parameters was drawn from the study. This is the first systemic study to evaluate the retinal changes in vivax malaria. Larger prospective studies should be done for further knowledge regarding retinal changes in vivax malaria, especially severe disease. Apart from its clinical significance, it might lead to a better understanding of the pathogenesis of the systemic disease of vivax malaria.