Clinical and Histopathological Evaluation of a Rabbit Model for <i>Pythium insidiosum</i> Keratitis

Kalra, Paavan; Ahirwar, Lalit Kishore; Mittal, Ruchi; Ranjith, Konduri; Das, Shilpa; Manjulatha, Kodiganti; Bagga, Bhupesh; Mohamed, Ashik; Joseph, Joveeta; Sharma, Savitri

doi:10.1080/02713683.2019.1676911

Cited by 9 publications

(5 citation statements)

References 13 publications

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“…Various treatment and management options have been proposed for treatment of Pythium keratitis. [ 1 2 7 8 9 10 11 12 16 20 21 ] Bagga et al . showed that the proportion of healed ulcers were more 35.2% with antibacterial treatment as compared to 15.3% with antifungal treatment.…”

Section: Discussionmentioning

confidence: 99%

Retrospective multifactorial analysis of Pythium keratitis and review of literature

Gurnani

Christy

Narayana

et al. 2021

Indian Journal of Ophthalmology

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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.

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Section: Discussionmentioning

confidence: 99%

Retrospective multifactorial analysis of Pythium keratitis and review of literature

Gurnani

Christy

Narayana

et al. 2021

Indian Journal of Ophthalmology

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“…As these medications were found to be safe in previously conducted in vivo (rabbit model of Pythium keratitis) and clinical trials (in patients), we have not performed any safety assessment for this study. 5,9,12,14 It was a double-masked, randomized, prospective clinical trial, that is, allotment of a patient into any study group was concealed and performed by the microbiologist along with dispensing of the study medications in look-alike bottles to mask both physician and patient about the treatment. Randomization was performed using a random allocation table (generated by a computer allocation table) by the microbiologist who also dispensed medication to both groups in look-alike dispensers.…”

Section: Methodsmentioning

confidence: 99%

“…Most of these cases necessitate early surgical intervention with further poorer prognosis and loss of the eye. 7,8 With in vitro analysis 9 and further in vivo 9 studies, efficacy of antibiotics was established in the treatment of Pythium keratitis. 5 In view of the severity of these infections at presentation, a combination of linezolid and azithromycin was selected for the management of Pythium keratitis.…”

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confidence: 99%

Randomized Double-Masked Placebo-Controlled Trial for the Management of Pythium Keratitis: Combination of Antibiotics Versus Monotherapy

Tanna

Bagga

Sharma

et al. 2023

Cornea

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Purpose:The aim of this study was to compare the efficacy of monotherapy (topical linezolid 0.2%) versus a combination of antibiotics (topical linezolid 0.2% and topical azithromycin 1%) for the treatment of Pythium insidiosum keratitis.Methods:Cases of P. insidiosum keratitis were prospectively randomized into group A on topical 0.2% linezolid along with topical placebo (sodium carboxymethyl cellulose [CMC] 0.5%) and group B on a combination of topical 0.2% linezolid and topical 1% azithromycin. Both groups were compared by proportion of both clinical resolution and worsening of keratitis along with the number of therapeutic penetrating keratoplasty (TPK) performed at 3 months.Results:We initially planned N = 66 patients but later limited to 20 (N = 10 in each group) patients owing to one interim analysis. The average size of the infiltrate in group A and B was 5.6 ± 1.5 mm and 4.8 ± 2.0 mm, respectively, with a mean Logarithm of the Minimum Angle of Resolution (logMAR) visual acuity of 2.74 ± 0.55 and 1.79 ± 1.19. At 3 months, from group A, 7 (70%) patients needed TPK and 2 patients had signs of resolution, whereas from group B, 6 (60%) patients achieved complete resolution (P = 0.0003) and 2 were improving while only 1 needed TPK (P = 0.02). The median duration of treatment in group A and B, with the study drugs, was 31 days (17.8–47.8) and 101.5 days (80–123.3), P value = 0.003, respectively. Final visual acuity at 3 months was 2.50 ± 0.81 and 0.75 ± 0.87, P = 0.02, respectively.Conclusions:A combination of topical linezolid and topical azithromycin was found to have superior efficacy than the monotherapy with topical linezolid for the management of Pythium keratitis.

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“…Corneal pathology scores were graded as following: a sprinkling of inflammatory cells affecting ≤1/4 of the corneal tissue was scored as minimal (1), with dense packing of inflammatory cells affecting 1/4–1/2, 1/2–3/4, and ≥3/4 of corneal stromal tissue was recorded as mild, moderate and severe (2, 3, 4) respectively. 29 , 30 The iris and ciliary body were graded for signs of swelling and inflammatory cell infiltration from normal (0) to severe (4).…”

Section: Methodsmentioning

confidence: 99%

Treatment of Severe Acute Bacterial Keratitis in Rabbits Using Continuous Topical Ocular Instillation with Norvancomycin

Lin

Zhao

Tan

et al. 2021

DDDT

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Purpose Efficacy of norvancomycin (NVCM) through continuous topical ocular instillation drug delivery (CTOIDD) system for treating severe acute bacterial keratitis infection with Staphylococcus aureus was investigated. Methods Rabbits with bacterial keratitis were treated using CTOIDD with NVCM (n=13), topical NVCM eye drops (n=11), and CTOIDD with saline (n=8). Clinical signs of keratitis in all groups were assessed consecutively for a week. Bacterial quantification of excised corneas was counted on the fourth and eighth days. Histopathologic examinations were performed to assess inflammatory cell infiltration on the eighth day. Results All signs of bacterial keratitis were alleviated in CTOIDD with NVCM according to criteria, and the CTOIDD-NVCM group had significantly less inflammation than CTOIDD-saline ( p <0.05), and eye drop-NVCM ( p <0.05). Two eyes in the eye drop-NVCM group, four eyes in the CTOIDD-saline group had corneal perforation (CP), while none of the rabbits showed CP in the CTOIDD-NVCM group. Bacterial counts were significantly less in the CTOIDD with NVCM group in comparison to the eye drop-NVCM ( p <0.05), and CTOIDD-saline ( p <0.05) groups. Severe inflammation and marked inflammatory cell infiltration were found in histopathologic examinations in the CTOIDD-saline and eye drop-NVCM groups, while significantly less inflammation was documented in the CTOIDD-NVCM ( p <0.05) group. Conclusion CTOIDD with NVCM effectively reduced the severity and treated acute bacterial S. aureus keratitis infection in a rabbit model. The presented approach of CTOIDD with NVCM appears to be a promising therapeutic approach for severe acute bacterial keratitis.

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

Cited by 9 publications

References 13 publications

Retrospective multifactorial analysis of Pythium keratitis and review of literature

Retrospective multifactorial analysis of Pythium keratitis and review of literature

Randomized Double-Masked Placebo-Controlled Trial for the Management of Pythium Keratitis: Combination of Antibiotics Versus Monotherapy

Treatment of Severe Acute Bacterial Keratitis in Rabbits Using Continuous Topical Ocular Instillation with Norvancomycin

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