Purpose: The aim of this work was to study the demographic profile, clinical diagnostic features, challenges in management, treatment outcomes, and ocular morbidity of microbiological culture-proven Pythium keratitis in a tertiary eye care hospital in South India. Methods: Retrospective analysis of microbiologically proven Pythium keratitis patients was performed at a tertiary eye center from October 2017 to March 2020. Demographic details, risk factors, microbiological investigations, clinical course, and visual outcomes were analyzed. Results: Thirty patients were analyzed. The mean age was 43.1±17.2 years. Most common risk factors were history of injury in 80% and exposure to dirty water in 23.3%. Visual acuity at baseline was 20/30 to perception of light (PL). The most common clinical presentation was stromal infiltrate and hypopyon in 14 (46.6%) patients each. The microbiological confirmation was based on culture on blood agar and vesicles with zoospores formation with incubated leaf carnation method. Seven (23.3%) patients improved with topical 0.2% Linezolid and topical 1% Azithromycin, 19 (63.3%) patients underwent Therapeutic keratoplasty (TPK) and 4 were lost to follow-up. Seven (23.3%) patients had graft reinfection, and 3 (10%) developed endophthalmitis. The final visual acuity was 20/20- 20/200 in 6 (20%) patients, 20/240-20/1200 in 5 (16.6%) patients, hand movement to positive perception of light in 16 patients and no perception of light (Pthisis Bulbi) in 3 (10%) patients. Conclusion: P. insidiosum keratitis is a rapidly progressive infectious keratitis with prolonged and relapsing clinical course. It usually results in irreparable vision loss in majority of the patients. Prompt diagnosis, clinical awareness, and specific treatment options are needed for successfully managing this devastating corneal disease.

Purpose: Pythium insidiosum causes a rare sight-threatening keratitis and is a devastating ocular pathology with a high morbidity. It is frequently mistaken as fungal keratitis. Here we highlight a rare case of pediatric Pythium insidiosum keratitis which was successfully managed using an antibiotic combination of linezolid and azithromycin with cyanoacrylate glue. Case description: A 9-year-old young male child presented to our clinic with defective vision, pain, redness in the right eye for 5 days post stick injury. In the right eye, Snellen’s best-corrected visual acuity (BCVA) was 6/12 which deteriorated to hand movements within 5 days of treatment. Ocular examination revealed 6 × 5 mm dry-looking mid stromal corneal infiltrate with feathery margin involving the visual axis. The clinical picture was suggestive of fungal keratitis. Corneal scraping and smear examination with 10% KOH and Gram stain revealed long slender hyaline hyphae with sparse septations. Before the culture result, the patient was started on 5% Natamycin and 1% Itraconazole hourly, but still, the infiltrate progressed. Further, P. Insidiosum keratitis was considered as the differential, which was confirmed on blood agar culture. After receiving culture results, the patient was managed with 0.2% Linezolid and 1% Azithromycin hourly. Due to the rapid progression of infiltrate, corneal melt, and younger age, cyanoacrylate glue, and bandage contact lens were used. On the last follow-up, the BCVA recovered to 6/12. Conclusion and importance: Prompt diagnosis, clinical awareness, and a specific treatment regime is needed for managing this devastating corneal entity. Cyanoacrylate glue due to its antibacterial properties can be a potential rescuer and can be considered for managing these cases.

The aim of our retrospective study is to report a case series of ocular infections caused by a rare fungus, Scedosporium apiospermum, in a South Indian population. Thirteen cases of culture-positive S. apiospermum infections diagnosed between January 2011 and March 2016 were included in this study. The parameters evaluated were predisposing factors, treatment and final clinical outcome. The most common mode of presentation was keratitis (84.6%) followed by sclerokeratitis (15.3%). The predisposing factors involved were unspecified foreign body injury (30.7%), organic matter injury (15.3%), uncontrolled diabetes (7.6%), and recent manual small-incision cataract surgery (7.6%). Five cases (38.46%) had no predisposing factor. Of the 11 keratitis cases, nine (69.2%) responded well to combination medical therapy while one case (7.6%) required therapeutic keratoplasty. One case was lost to follow-up. Both cases which presented with sclerokeratitis showed no response to medico-surgical treatment progressing to panophthalmitis and evisceration.

Pythium insidiosum (PI) is an oomycete, a protist belonging to the clade Stramenopila. PI causes vision-threatening keratitis closely mimicking fungal keratitis (FK), hence it is also labeled as “parafungus”. PI keratitis was initially confined to Thailand, USA, China, and Australia, but with growing clinical awareness and improvement in diagnostic modalities, the last decade saw a massive upsurge in numbers with the majority of reports coming from India. In the early 1990s, pythiosis was classified as vascular, cutaneous, gastrointestinal, systemic, and ocular. Clinically, morphologically, and microbiologically, PI keratitis closely resembles severe FK and requires a high index of clinical suspicion for diagnosis. The clinical features such as reticular dot infiltrate, tentacular projections, peripheral thinning with guttering, and rapid limbal spread distinguish it from other microorganisms. Routine smearing with Gram and KOH stain reveals perpendicular septate/aseptate hyphae, which closely mimic fungi and make the diagnosis cumbersome. The definitive diagnosis is the presence of dull grey/brown refractile colonies along with zoospore formation upon culture by leaf induction method. However, culture is time-consuming, and currently polymerase chain reaction (PCR) method is the gold standard. The value of other diagnostic modalities such as confocal microscopy and immunohistopathological assays is limited due to cost, non-availability, and limited diagnostic accuracy. PI keratitis is a relatively rare disease without established treatment protocols. Because of its resemblance to fungus, it was earlier treated with antifungals but with an improved understanding of its cell wall structure and absence of ergosterol, this is no longer recommended. Currently, antibacterials have shown promising results. Therapeutic keratoplasty with good margin (1 mm) is mandated for non-resolving cases and corneal perforation. In this review, we have deliberated on the evolution of PI keratitis, covered all the recently available literature, described our current understanding of the diagnosis and treatment, and the potential future diagnostic and management options for PI keratitis.