1
|
Gurnani B, Kaur K. Understanding barriers, recommended solutions, and future prospects for the diagnosis and management of Pythium insidiosum keratitis. Indian J Ophthalmol 2023; 71:3584-3586. [PMID: 37991287 PMCID: PMC10788758 DOI: 10.4103/ijo.ijo_1041_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/31/2023] [Accepted: 08/04/2023] [Indexed: 11/23/2023] Open
Abstract
Pythium insidiosum keratitis (PIK) is a devastating corneal infection resulting in blindness in a large number of cases. Clinically and morphologically, it closely mimics fungal keratitis, and hence is also labeled as "parafungus." Although many clinical studies have documented evidence regarding the virulence of microorganism, and anatomical and functional outcomes, it remains a clinical challenge and diagnostic dilemma for most clinicians. Till today, PIK is being diagnosed and treated with certainty at only limited centers across the globe. But the question is why this is so? Taking this as the research question, this section on current ophthalmology aims to highlight the understanding of barriers to diagnosing and treating PIK, the suggestions to improve diagnosis and treatment, and the future prospects.
Collapse
Affiliation(s)
- Bharat Gurnani
- Cataract, Cornea, Trauma, External Disease, Ocular Surface and Refractive Services, Sadguru Netra Chikitsalya, Shri Sadguru Seva Sangh Trust, Chitrakoot, Madhya Pradesh, India
| | - Kirandeep Kaur
- Cataract, Pediatrics Ophthalmology and Strabismus Services, Sadguru Netra Chikitsalya, Shri Sadguru Seva Sangh Trust, Chitrakoot, Madhya Pradesh, India
| |
Collapse
|
2
|
Gurnani B, Kaur K. Predicting Prognosis Based on Regional Prevalence, Ulcer Morphology and Treatment Strategy in Vision-Threatening Pythium insidiosum Keratitis. Clin Ophthalmol 2023; 17:1307-1314. [PMID: 37181081 PMCID: PMC10167989 DOI: 10.2147/opth.s412274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 04/24/2023] [Indexed: 05/16/2023] Open
Abstract
Pythium insidiosum is an oomycete belonging to the phylum Straminipila and family Pythiaceae. It causes rapidly progressive vision-threatening keratitis. Clinically, microbiologically and morphologically, it closely resembles fungal keratitis; hence it is also labelled as a "parafungus". The clinical features mimicking fungus are subepithelial and stromal infiltrate, endo-exudates, corneal melt and hypopyon. The hallmark features of Pythium are tentacular projections, reticular dot-like infiltrate, peripheral furrowing and thinning, and rapid limbal spread. Microbiological corneal smearing on KOH and Gram stain reveal septate or aseptate, obtuse to perpendicular hyphae which mimic fungal hyphae. Culture on any nutritional agar reveals cream, cottonwool-like, fluffy colonies, and diagnosis is confirmed by zoospore formation by the leaf incarnation method. Medical management with antifungals and antibacterials still presents a dilemma. Early therapeutic keratoplasty has been the proposed treatment in most cases. We hypothesize that the prognosis of Pythium keratitis is governed by regional geographical variations, ulcer size and density on presentation, and initial treatment strategy. The available literature supporting the proposed hypothesis is also discussed, along with the hallmark features of Pythium and how it masquerades as other microorganisms causing keratitis. We also aim to propose a novel diagnostic and treatment algorithm for managing this vision-threatening keratitis.
Collapse
Affiliation(s)
- Bharat Gurnani
- Department of Cornea and Refractive Surgery, Sadguru Netra Chikitsalya, Shri Sadguru Seva Sangh Trust, Chitrakoot, Madhya Pradesh, 485334, India
| | - Kirandeep Kaur
- Department of Pediatric Ophthalmology, Sadguru Netra Chikitsalya, Shri Sadguru Seva Sangh Trust, Chitrakoot, Madhya Pradesh, 485334, India
| |
Collapse
|
3
|
Agarwal S, Pandey S, Srinivasan B, Anand AR, Iyer G. Possible Synergistic Role of Cryo-Alcohol Therapy in Infectious Scleritis-Scope and Rationale for Expanding Indications and Review of the Literature. Cornea 2023; 42:194-203. [PMID: 35249984 DOI: 10.1097/ico.0000000000003007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 01/10/2022] [Indexed: 01/03/2023]
Abstract
PURPOSE The purpose of this study was to highlight the use of topical ethanol as an adjunct to cryotherapy, termed cryo-alcohol therapy, in the management of fungal/acanthamoeba scleritis along with a review of the literature. METHOD Retrospective interventional case reports of fungal and acanthamoeba scleritis along with a review of the literature. RESULTS The patient with circumferential necrotic fungal scleritis resolved in 6 weeks achieving a best-corrected visual acuity (BCVA) of 20/20, and the patient with acanthamoeba scleritis is awaiting optical keratoplasty after complete resolution in 8 weeks. The literature review from January 1990 to December 2020 revealed BCVA >20/200 in 50% of the eyes with a mean time to resolution being 4.16 ± 2.13 months in fungal scleritis, with 27.02% and 75% of the eyes requiring evisceration in fungal and acanthamoeba scleritis, respectively. CONCLUSIONS Cryotherapy is a useful adjunct in managing refractory infectious scleritis, and its efficacy can be enhanced by combining the use of topical ethanol to aid in faster recovery and reduce visual morbidity.
Collapse
Affiliation(s)
- Shweta Agarwal
- Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, CJ Shah Cornea Services, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India ; and
| | - Sunita Pandey
- Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, CJ Shah Cornea Services, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India ; and
| | - Bhaskar Srinivasan
- Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, CJ Shah Cornea Services, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India ; and
| | - Appakkudal R Anand
- L and T Microbiology Research Centre, Vision Research Foundation, Sankara Nethralaya, Chennai, India
| | - Geetha Iyer
- Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, CJ Shah Cornea Services, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India ; and
| |
Collapse
|
4
|
Cao B, Gonugunta VT, Radhakrishnan N, Lalitha P, Gurnani B, Kaur K, Iyer G, Agarwal S, Srinivasan B, Keenan JD, Prajna NV. Outcomes of Pythium keratitis: a meta-analysis of individual patient data. CURRENT OPHTHALMOLOGY REPORTS 2022; 10:198-208. [PMID: 37250102 PMCID: PMC10211475 DOI: 10.1007/s40135-022-00302-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2022] [Indexed: 11/11/2022]
Abstract
Background Pythium keratitis is a difficult-to-treat corneal infection. Methods A meta-analysis of individual patient data from observational studies of Pythium keratitis was performed. The outcomes of interest were therapeutic penetrating keratoplasty (TPK) and globe removal (evisceration, enucleation, or exenteration); the main exposures were linezolid and azithromycin use. Findings Of 46 eligible articles, individual patient data were available for 306 eyes (34 studies). Pythium keratitis was associated with high rates of TPK (80%, 95%CI 70-87%) and globe removal (25%, 95%CI 13-43). In multivariable models adjusting for age and country, fewer TPKs were performed in patients treated with azithromycin (RR=0.80, 95%CI 0.67-0.96; P=0.04) and linezolid (RR=0.82, 95%CI 0.67-0.99; P=0.02). Conclusions Studies of Pythium keratitis reported high rates of TPK and globe removal. Use of azithromycin and linezolid was associated with a lower rate of TPK. While promising, these results should be interpreted with caution given the biases inherent to observational studies.
Collapse
Affiliation(s)
- Binh Cao
- Francis I Proctor Foundation, University of California, San Francisco, USA
| | | | - Naveen Radhakrishnan
- Department of Cornea and Refractive Surgery, Aravind Eye Hospital Madurai, India
| | - Prajna Lalitha
- Department of Ocular Microbiology, Aravind Eye Hospital Madurai, India
| | - Bharat Gurnani
- Dr. Om Parkash Eye Institute, Amritsar, India
- Aravind Eye Hospital and Post Graduate Institute, Pondicherry, India
| | - Kirandeep Kaur
- Dr. Om Parkash Eye Institute, Amritsar, India
- Aravind Eye Hospital and Post Graduate Institute, Pondicherry, India
| | - Geetha Iyer
- C J Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Sankara Nethralaya, Chennai, India
| | - Shweta Agarwal
- C J Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Sankara Nethralaya, Chennai, India
| | - Bhaskar Srinivasan
- C J Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Sankara Nethralaya, Chennai, India
| | - Jeremy D Keenan
- Francis I Proctor Foundation, University of California, San Francisco, USA
- Department of Ophthalmology, University of California, San Francisco, USA
| | - N Venkatesh Prajna
- Department of Cornea and Refractive Surgery, Aravind Eye Hospital Madurai, India
| |
Collapse
|
5
|
Yolanda H, Lohnoo T, Rujirawat T, Yingyong W, Kumsang Y, Sae-Chew P, Payattikul P, Krajaejun T. Selection of an Appropriate In Vitro Susceptibility Test for Assessing Anti- Pythium insidiosum Activity of Potassium Iodide, Triamcinolone Acetonide, Dimethyl Sulfoxide, and Ethanol. J Fungi (Basel) 2022; 8:1116. [PMID: 36354883 PMCID: PMC9692648 DOI: 10.3390/jof8111116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/12/2022] [Accepted: 10/13/2022] [Indexed: 02/12/2024] Open
Abstract
The orphan but highly virulent pathogen Pythium insidiosum causes pythiosis in humans and animals. Surgery is a primary treatment aiming to cure but trading off losing affected organs. Antimicrobial drugs show limited efficacy in treating pythiosis. Alternative drugs effective against the pathogen are needed. In-house drug susceptibility tests (i.e., broth dilution, disc diffusion, and radial growth assays) have been established, some of which adapted the standard protocols (i.e., CLSI M38-A2 and CLSI M51) designed for fungi. Hyphal plug, hyphal suspension, and zoospore are inocula commonly used in the drug susceptibility assessment for P. insidiosum. A side-by-side comparison demonstrated that each method had advantages and limitations. Minimum inhibitory and cidal concentrations of a drug varied depending on the selected method. Material availability, user experience, and organism and drug quantities determined which susceptibility assay should be used. We employed the hyphal plug and a combination of broth dilution and radial growth methods to screen and validate the anti-P. insidiosum activities of several previously reported chemicals, including potassium iodide, triamcinolone acetonide, dimethyl sulfoxide, and ethanol, in which data on their anti-P. insidiosum efficacy are limited. We tested each chemical against 29 genetically diverse isolates of P. insidiosum. These chemicals possessed direct antimicrobial effects on the growth of the pathogen in a dose- and time-dependent manner, suggesting their potential application in pythiosis treatment. Future attempts should focus on standardizing these drug susceptibility methods, such as determining susceptibility/resistant breakpoints, so healthcare workers can confidently interpret a result and select an effective drug against P. insidiosum.
Collapse
Affiliation(s)
- Hanna Yolanda
- Program in Translational Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
- Department of Parasitology, School of Medicine and Health Sciences, Atma Jaya Catholic University of Indonesia, Jakarta 14440, Indonesia
| | - Tassanee Lohnoo
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Thidarat Rujirawat
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Wanta Yingyong
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Yothin Kumsang
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Pattarana Sae-Chew
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Penpan Payattikul
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Theerapong Krajaejun
- Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| |
Collapse
|
6
|
Gurnani B, Kaur K, Agarwal S, Lalgudi VG, Shekhawat NS, Venugopal A, Tripathy K, Srinivasan B, Iyer G, Gubert J. Pythium insidiosum Keratitis: Past, Present, and Future. Ophthalmol Ther 2022; 11:1629-1653. [PMID: 35788551 PMCID: PMC9255487 DOI: 10.1007/s40123-022-00542-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/15/2022] [Indexed: 11/30/2022] Open
Abstract
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.
Collapse
Affiliation(s)
- Bharat Gurnani
- Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Pondicherry, 605007, India.
| | - Kirandeep Kaur
- Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Pondicherry, 605007 India
| | - Shweta Agarwal
- Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, CJ Shah Cornea Services, Medical Research Foundation, Sankara Nethralaya, 18 College Road, Chennai, Tamil Nadu 600006 India
| | | | - Nakul S. Shekhawat
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Anitha Venugopal
- Aravind Eye Hospital and Postgraduate Institute of Ophthalmology, Tirunelveli, Tamil Nadu India
| | | | - Bhaskar Srinivasan
- Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, CJ Shah Cornea Services, Medical Research Foundation, Sankara Nethralaya, 18 College Road, Chennai, Tamil Nadu 600006 India
| | - Geetha Iyer
- Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, CJ Shah Cornea Services, Medical Research Foundation, Sankara Nethralaya, 18 College Road, Chennai, Tamil Nadu 600006 India
| | - Joseph Gubert
- Department of Microbiology, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Pondicherry, 605007 India
| |
Collapse
|
7
|
Yolanda H, Krajaejun T. Global Distribution and Clinical Features of Pythiosis in Humans and Animals. J Fungi (Basel) 2022; 8:jof8020182. [PMID: 35205934 PMCID: PMC8879638 DOI: 10.3390/jof8020182] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/06/2022] [Accepted: 02/08/2022] [Indexed: 01/27/2023] Open
Abstract
Pythiosis is a difficult-to-treat infectious disease caused by Pythium insidiosum. The condition is unfamiliar among healthcare workers. Manifestation of pythiosis is similar to other fungal infections, leading to misdiagnosis and delayed treatment. The geographical extent of pythiosis at a global scale is unclear. This study aimed to analyze the clinical information recorded in the scientific literature to comprehensively project epidemiological characteristics, clinical features, and future trends of pythiosis. From 1980 to 2021, 4203 cases of pythiosis in humans (n = 771; 18.3%) and animals (primarily horse, dog, and cow; n = 3432; 81.7%), with an average of 103 cases/year, were recruited. Pythiosis case reports significantly increased in the last decade. Pythiosis spanned 23 tropical, subtropical, and temperate countries worldwide. Some patients acquired pythiosis from a trip to an endemic country. Strikingly, 94.3% of human cases were in India and Thailand, while 79.2% of affected animals were in the U.S.A. and Brazil. Clinical features of pythiosis varied. Vascular and ocular pythiosis were only observed in humans, whereas cutaneous/subcutaneous and gastrointestinal infections were predominant in animals. Mortality depended on host species and clinical forms: for example, none in patients with ocular pythiosis, 0.7% in cows with a cutaneous lesion, 26.8% in humans with vascular disease, 86.4% in dogs with gastrointestinal pathology, and 100% in several animals with disseminated infection. In summary, this study reports up-to-date epidemiological and clinical features of pythiosis in humans and animals. It increases awareness of this life-threatening disease, as the illness or outbreak can exist in any country, not limited to the endemic areas.
Collapse
Affiliation(s)
- Hanna Yolanda
- Program in Translational Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand;
- Department of Parasitology, School of Medicine and Health Sciences, Atma Jaya Catholic University of Indonesia, Jakarta 14440, Indonesia
| | - Theerapong Krajaejun
- Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
- Correspondence: ; Tel.: +662-201-1452
| |
Collapse
|
8
|
Topical use of alcohol in ophthalmology - Diagnostic and therapeutic indications. Ocul Surf 2021; 21:1-15. [PMID: 33895368 DOI: 10.1016/j.jtos.2021.04.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 04/14/2021] [Accepted: 04/16/2021] [Indexed: 01/02/2023]
Abstract
Alcohol (ethanol) has been used in medicine since time immemorial. In ophthalmic practice, besides as an antiseptic, it was given as retrobulbar injections to relieve severe ocular pain. Alcohol can be applied topically to the surface of neoplastic or suspicious lesions to kill cells that might desquamate and seed during surgical excision, to treat epithelial ingrowth that can occur following corneal surgeries, particularly laser in situ keratomileusis (LASIK), and to treat superficial infectious keratitis. In view of its ability to achieve a smooth cleavage plane between the epithelium and the Bowman's layer, alcohol-assisted delamination (ALD) of the corneal epithelium has been used widely and effectively for a variety of diagnostic and therapeutic indications, at times delivering both outcomes. Diagnostically, ALD yields an intact epithelial sheet which can be fixed flat to provide excellent orientation for histopathological evaluation. Therapeutically, it is most commonly used to treat recurrent corneal erosion syndrome, where its efficacy is comparable to that of phototherapeutic keratectomy but with several advantages. It has also been used to treat various forms of epithelial/anterior stromal dystrophies, which can obviate or delay the need for corneal transplantation for several years. In addition, ALD is performed in corneal collagen cross-linking and corneal refractive surgery for relatively atraumatic removal of the epithelium. In this review, we aimed to provide a comprehensive overview of the diagnostic and therapeutic use of topical alcohol in ophthalmology, to describe the surgical and fixation techniques of ALD, and to highlight our experience in ALD over the past decade.
Collapse
|