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Gurnani B, Kaur K. Anti-infective therapies for Pythium insidiosum keratitis. Expert Rev Anti Infect Ther 2024:1-13. [PMID: 39268901 DOI: 10.1080/14787210.2024.2403146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Accepted: 09/08/2024] [Indexed: 09/15/2024]
Abstract
INTRODUCTION Pythium insidiosum keratitis (PIK) is a rapidly progressing ocular disease predominantly found in tropical and subtropical regions. Characterized by severe corneal damage and high morbidity, this infection poses significant challenges in diagnosis and management, necessitating effective anti-infective therapies. AREAS COVERED This report delves into the pathophysiology, clinical and microbiological diagnosis, and detailed insights into the anti-infective therapy for PIK, outlining current diagnostic challenges that complicate treatment. We review existing anti-infective therapies, including their efficacy and limitations, and discuss the role of surgical interventions in managing advanced cases. The report also highlights ongoing research into novel treatment approaches and the critical need for developing targeted therapies. EXPERT OPINION Despite advances in understanding PIK, treatment remains complex due to pathogen resistance and diagnostic hurdles. Future research should focus on innovative anti-infective strategies, improved diagnostic techniques, and global surveillance to enhance therapeutic outcomes. Collaboration between ophthalmologists, microbiologists, and pharmacologists is essential to advance treatment protocols and improve patient prognosis.
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Affiliation(s)
- Bharat Gurnani
- Cataract, Cornea, Refractive Services, Trauma, External Diseases, Contact Lens and Ocular Surface, Gomabai Netralaya, Neemuch, India
| | - Kirandeep Kaur
- Cataract, Pediatric Ophthalmology and Strabismus, Gomabai Netralaya, Neemuch, India
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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.
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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
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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.
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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
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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.
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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
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Chatterjee S, Agrawal D, Gomase SN. Clinical differentiation of Pythium keratitis from fungal keratitis and development of a scoring system. Indian J Ophthalmol 2022; 70:3515-3521. [PMID: 36190038 PMCID: PMC9789832 DOI: 10.4103/ijo.ijo_870_22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Purpose To differentiate Pythium keratitis from fungal keratitis using clinical signs, to explore usefulness of various signs as diagnostic prognosticators, and develop a clinical scoring system. Methods A retrospective review of medical records and archived clinical photographs of patients with culture-positive Pythium keratitis and hyaline filamentous fungal keratitis was conducted at a tertiary eye institute to explore characteristics of ulcers that may aid diagnosis. Results Full-thickness corneal stromal keratitis (P = 0.055), a dry ulcer surface (P = 0.010), tentacles (P < 0.0001), intrastromal dots (P < 0.0001), ring infiltrates (P = 0.024), reticular patterns (P < 0.0001), and peripheral furrows (P < 0.0001) were clinical signs associated with Pythium keratitis. Multiple regression analysis identified tentacles (odds ratio: 24.1, 95% confidence interval (CI): 3.8-158.1, P = 0.001) and peripheral furrows (odds ratio: 60.6, 95% CI: 5.1-712.3, P = 0.001) as independent diagnostic prognosticators for Pythium keratitis. The positive and negative likelihood ratios of a dry ulcer surface, tentacles, intrastromal dots, ring infiltrates, reticular patterns, and peripheral furrows predicting Pythium keratitis were 1.6, 13.6, 17.9, 4.3, 30.7, 15.3 and 0.4, 0.4, 0.7, 0.9, 0.6 and 0.8, respectively. The presence of two or more of these clinical signs (excluding a dry ulcer surface) had a sensitivity of 55.6% and a false positive rate of 1.4%. Conclusion Tentacles, intrastromal dots, ring infiltrates, reticular patterns, and peripheral furrows are clinical signs to be considered for the diagnosis of Pythium keratitis and the presence of two or more signs has a very low false positive rate.
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Affiliation(s)
- Samrat Chatterjee
- Cornea and Anterior Segment Services, MGM Eye Institute, Raipur, Chhattisgarh, India,Correspondence to: Dr. Samrat Chatterjee, Cornea and Anterior Segment Services, MGM Eye Institute, 5th Mile, Vidhan Sabha Road, Raipur - 493 111, Chhattisgarh, India. E-mail:
| | - Deepshikha Agrawal
- Cornea and Anterior Segment Services, MGM Eye Institute, Raipur, Chhattisgarh, India
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Severe skin and soft tissue pythiosis acquired in a hot sp. Travel Med Infect Dis 2022; 48:102349. [DOI: 10.1016/j.tmaid.2022.102349] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 03/25/2022] [Accepted: 04/25/2022] [Indexed: 12/14/2022]
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Gurnani B, Kaur K, Venugopal A, Srinivasan B, Bagga B, Iyer G, Christy J, Prajna L, Vanathi M, Garg P, Narayana S, Agarwal S, Sahu S. Pythium insidiosum keratitis - A review. Indian J Ophthalmol 2022; 70:1107-1120. [PMID: 35325996 PMCID: PMC9240499 DOI: 10.4103/ijo.ijo_1534_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Pythium insidiosum is an oomycete and is also called “parafungus” as it closely mimics fungal keratitis. The last decade saw an unprecedented surge in Pythium keratitis cases, especially from Asia and India, probably due to growing research on the microorganism and improved diagnostic and treatment modalities. The clinical features such as subepithelial infiltrate, cotton wool-like fluffy stromal infiltrate, satellite lesions, corneal perforation, endoexudates, and anterior chamber hypopyon closely resemble fungus. The classical clinical features of Pythium that distinguish it from other microorganisms are reticular dots, tentacular projections, peripheral furrowing, and early limbal spread, which require a high index of clinical suspicion. Pythium also exhibits morphological and microbiological resemblance to fungus on routine smearing, revealing perpendicular or obtuse septate or aseptate branching hyphae. Culture on blood agar or any other nutritional agar is the gold standard for diagnosis. It grows as cream-colored white colonies with zoospores formation, further confirmed using the leaf incarnation method. Due to limited laboratory diagnostic modalities and delayed growth on culture, there was a recent shift toward various molecular diagnostic modalities such as polymerase chain reaction, confocal microscopy, ELISA, and immunodiffusion. As corneal scraping (10% KOH, Gram) reveals fungal hyphae, antifungals are started before the culture results are available. Recent in vitro molecular studies have suggested antibacterials as the first-line drugs in the form of 0.2% linezolid and 1% azithromycin. Early therapeutic keratoplasty is warranted in nonresolving cases. This review aims to describe the epidemiology, clinical features, laboratory and molecular diagnosis, and treatment of Pythium insidiosum keratitis.
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Affiliation(s)
- Bharat Gurnani
- Cataract, Cornea, External Disease, Trauma and Refractive Services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Pondicherry, India
| | - Kirandeep Kaur
- Pediatric and Squint Services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Pondicherry, India
| | - Anitha Venugopal
- Cornea, Ocular surface, Trauma and Refractive services, 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, Chennai, Tamil Nadu, India
| | - Bhupesh Bagga
- Cornea Clinic, L V Prasad Eye Institute, Kallam Anji Reddy Campus, Hyderabad, Telangana, 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
| | - Josephine Christy
- Cataract, Cornea and Refractive Services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Pondicherry, India
| | - Lalitha Prajna
- Microbiology Services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Madurai, Tamil Nadu, India
| | - Murugesan Vanathi
- Cornea and Ocular Surface, Cataract and Refractive Services, Dr R P Centre, AIIMS, New Delhi, India
| | - Prashant Garg
- Director and Kallam Anji Reddy Chair of Ophthalmology Paul Dubord Chair of Cornea, L V Prasad Eye Institute, Kallam Anji Reddy Campus, Hyderabad, Telangana, India
| | - Shivanand Narayana
- Cataract, Cornea, External Diseases, Trauma and Refractive Services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Pondicherry, India
| | - Shweta Agarwal
- Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, CJ Shah Cornea Services, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Srikant Sahu
- Cornea and Anterior Segment, Contact Lens, Cataract, Laser Refractive Surgery Services, Mithu Tulsi Chanrai Campus, LV Prasad Eye Institute, Bhubaneswar, Orissa, India
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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: 23] [Impact Index Per Article: 11.5] [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.
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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
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History and Perspective of Immunotherapy for Pythiosis. Vaccines (Basel) 2021; 9:vaccines9101080. [PMID: 34696188 PMCID: PMC8539095 DOI: 10.3390/vaccines9101080] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/27/2021] [Accepted: 09/08/2021] [Indexed: 12/24/2022] Open
Abstract
The fungus-like microorganism Pythium insidiosum causes pythiosis, a life-threatening infectious disease increasingly reported worldwide. Antimicrobial drugs are ineffective. Radical surgery is an essential treatment. Pythiosis can resume post-surgically. Immunotherapy using P. insidiosum antigens (PIA) has emerged as an alternative treatment. This review aims at providing up-to-date information of the immunotherapeutic PIA, with the focus on its history, preparation, clinical application, outcome, mechanism, and recent advances, in order to promote the proper use and future development of this treatment modality. P. insidiosum crude extract is the primary source of immunotherapeutic antigens. Based on 967 documented human and animal (mainly horses) pythiosis cases, PIA immunotherapy reduced disease morbidity and mortality. Concerning clinical outcomes, 19.4% of PIA-immunized human patients succumbed to vascular pythiosis instead of 41.0% in unimmunized cases. PIA immunotherapy may not provide an advantage in a local P. insidiosum infection of the eye. Both PIA-immunized and unimmunized horses with pythiosis showed a similar survival rate of ~70%; however, demands for surgical intervention were much lesser in the immunized cases (22.8% vs. 75.2%). The proposed PIA action involves switching the non-protective T-helper-2 to protective T-helper-1 mediated immunity. By exploring the available P. insidiosum genome data, synthetic peptides, recombinant proteins, and nucleic acids are potential sources of the immunotherapeutic antigens worth investigating. The PIA therapeutic property needs improvement for a better prognosis of pythiosis patients.
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Kharel A, Islam MT, Rookes J, Cahill D. How to Unravel the Key Functions of Cryptic Oomycete Elicitin Proteins and Their Role in Plant Disease. PLANTS 2021; 10:plants10061201. [PMID: 34204633 PMCID: PMC8231210 DOI: 10.3390/plants10061201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/08/2021] [Accepted: 06/09/2021] [Indexed: 12/13/2022]
Abstract
Pathogens and plants are in a constant battle with one another, the result of which is either the restriction of pathogen growth via constitutive or induced plant defense responses or the pathogen colonization of plant cells and tissues that cause disease. Elicitins are a group of highly conserved proteins produced by certain oomycete species, and their sterol binding ability is recognized as an important feature in sterol–auxotrophic oomycetes. Elicitins also orchestrate other aspects of the interactions of oomycetes with their plant hosts. The function of elicitins as avirulence or virulence factors is controversial and is dependent on the host species, and despite several decades of research, the function of these proteins remains elusive. We summarize here our current understanding of elicitins as either defense-promoting or defense-suppressing agents and propose that more recent approaches such as the use of ‘omics’ and gene editing can be used to unravel the role of elicitins in host–pathogen interactions. A better understanding of the role of elicitins is required and deciphering their role in host–pathogen interactions will expand the strategies that can be adopted to improve disease resistance and reduce crop losses.
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Gurnani B, Christy J, Narayana S, Rajkumar P, Kaur K, Gubert J. Retrospective multifactorial analysis of Pythium keratitis and review of literature. Indian J Ophthalmol 2021; 69:1095-1101. [PMID: 33913840 PMCID: PMC8186601 DOI: 10.4103/ijo.ijo_1808_20] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
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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Affiliation(s)
- Bharat Gurnani
- Cornea and Refractive Surgery Services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Cuddalore Main Road, Thavalukuppam, Pondicherry, India
| | - Josephine Christy
- Cornea and Refractive Surgery Services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Cuddalore Main Road, Thavalukuppam, Pondicherry, India
| | - Shivananda Narayana
- Cornea and Refractive Surgery Services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Cuddalore Main Road, Thavalukuppam, Pondicherry, India
| | - Purushothama Rajkumar
- Cornea and Refractive Surgery Services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Cuddalore Main Road, Thavalukuppam, Pondicherry, India
| | - Kirandeep Kaur
- Pediatric Ophthalmology and Squint Fellow, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Cuddalore Main Road, Thavalukuppam, Pondicherry, India
| | - Joseph Gubert
- Department of Microbiology, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Cuddalore Main Road, Thavalukuppam, Pondicherry, India
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Predisposing Factors, Clinical Presentations, and Outcomes of Contact Lens-Related Pythium Keratitis. Cornea 2021; 40:1413-1419. [PMID: 33470674 DOI: 10.1097/ico.0000000000002651] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/24/2020] [Indexed: 11/26/2022]
Abstract
PURPOSE To describe predisposing factors, clinical presentations, and treatment outcomes of contact lens (CL)-related Pythium keratitis. METHODS This was an 11-year retrospective study of CL-related Pythium keratitis conducted from 2009 to 2019. Six eyes of 6 patients were identified. Demographics, predisposing factors, CL history, clinical presentation, diagnostic tests, treatments, and outcomes were reviewed. RESULTS Mean age of the patients was 34 years (SD 16.3 years) with equal proportion between male and female patients. Five of 6 patients (83.3%) used soft CL, whereas 1 patient used rigid gas permeable lens. All patients had a history of water contamination (tap water and water from river and sea). Mean duration from the onset was 7.8 days (range 4-14 days). Mean size of the corneal lesion was 3.33 mm (SD 1.31 mm) in width. The typical feature of tentacle-like lesions radiating in a reticular pattern was observed in all patients. Feathery edge (1 eye), satellite lesions (2 eyes), and radial keratoneuritis (2 eyes) were also found. Every patient received therapeutic penetrating keratoplasty because of failed medical treatments. One patient subsequently underwent enucleation. Globe salvage was achieved in 5 patients (83.33%). CONCLUSIONS Awareness of the history of water contamination, recognition of specific clinical features of Pythium keratitis, and performing surgical treatment are key for achieving globe salvage in patients with CL-related Pythium keratitis.
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Appavu SP, Prajna L, Rajapandian SGK. Genotyping and phylogenetic analysis of Pythium insidiosum causing human corneal ulcer. Med Mycol 2020; 58:211-218. [PMID: 31073609 DOI: 10.1093/mmy/myz044] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/21/2019] [Accepted: 04/11/2019] [Indexed: 11/13/2022] Open
Abstract
Pythium insidiosum belongs to the Oomycetes, which are known to cause serious life-threatening infectious condition in humans and animals. Corneal infections caused by P. insidiosum are rare and difficult to treat. The molecular-based diagnosis of Pythium is employed for the species identification and to study molecular phylogenetic relationship. Based on Cytochrome oxidase II (cox II) gene, P. insidiosum is categorized into three clades or groups: Clade-I or ATH (American strains), Clade-II or BTH (American, Asian, and Australian strains), and Clade-III or CTH (mostly Thailand strains). This study focused on the molecular identification of Pythium insidiosum from patients with corneal ulcer using ITS regions and clade identification by cox II gene sequencing and correlated with the clinical outcome. The isolates were collected from Aravind Eye Hospital, Madurai, India, from April to December 2018. Through the microbiological laboratory reports, 15 isolates of Pythium sp. from keratitis patient were selected, followed by DNA extraction, ITS, and cox II gene sequencing and phylogenetic analysis using the reference sequences from NCBI database. All 15 P. insidiosum isolates were phylogenetically clustered together as a single group and where also placed distantly from other Pythium species (outgroup). Most ocular isolates fell into either clade BTH or clade CTH, and none of our ocular isolates were in clade ATH. Two of the strains were very distinct and did not match any of the clusters indicating different lineages. There was no significant difference between clinical outcome and genotype of P. insidiosum.
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Affiliation(s)
| | - Lalitha Prajna
- Department of Microbiology, Aravind Eye Hospital, Madurai
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Chitasombat MN, Jongkhajornpong P, Lekhanont K, Krajaejun T. Recent update in diagnosis and treatment of human pythiosis. PeerJ 2020; 8:e8555. [PMID: 32117626 PMCID: PMC7036273 DOI: 10.7717/peerj.8555] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 01/13/2020] [Indexed: 12/20/2022] Open
Abstract
Human pythiosis is an infectious condition with high morbidity and mortality. The causative agent is the oomycete microorganism Pythium insidiosum. The pathogen inhabits ubiquitously in a wet environment, and direct exposure to the pathogen initiates the infection. Most patients with pythiosis require surgical removal of the affected organ, and many patients die from the disease. Awareness of pythiosis among healthcare personnel is increasing. In this review, we summarized and updated information on the diagnosis and treatment of human pythiosis. Vascular and ocular pythiosis are common clinical manifestations. Recognition of the typical clinical features of pythiosis is essential for early diagnosis. The definitive diagnosis of the disease requires laboratory testing, such as microbiological, serological, molecular, and proteomic assays. In vascular pythiosis, surgical intervention to achieve the organism-free margin of the affected tissue, in combination with the use of antifungal drugs and P. insidiosum immunotherapy, remains the recommended treatment. Ocular pythiosis is a serious condition and earliest therapeutic penetrating keratoplasty with wide surgical margin is the mainstay treatment. Thorough clinical assessment is essential in all patients to evaluate the treatment response and detect an early sign of the disease recurrence. In conclusion, early diagnosis and proper management are the keys to an optimal outcome of the patients with pythiosis.
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Affiliation(s)
- Maria Nina Chitasombat
- Division of Infectious Disease, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Passara Jongkhajornpong
- Department of Ophthalmology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Kaevalin Lekhanont
- Department of Ophthalmology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Theerapong Krajaejun
- Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
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Worasilchai N, Leelahavanichkul A, Permpalung N, Kuityo C, Phaisanchatchawan T, Palaga T, Reantragoon R, Chindamporn A. Antigen host response differences between the animal-type strain and human-clinical Pythium insidiosum isolates used for serological diagnosis in Thailand. Med Mycol 2019; 57:519-522. [PMID: 30165659 DOI: 10.1093/mmy/myy072] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 07/20/2018] [Accepted: 07/28/2018] [Indexed: 11/13/2022] Open
Abstract
The detection of Pythium insidiosum-specific-immunoglobulin-G antibody (Pi-Ab) with enzyme-linked immunosorbent assay (ELISA) test depends on the source of antigen. In this study, the Pi-Ab levels in 140 serum samples from patients with pythiosis were evaluated by ELISA using antigens from 10 P. insidiosum clinical isolates in comparison with antigen from the equine-standard-type strain. The ELISA values (EVs), calculated from antibody levels from serum of patients with pythiosis or other infections versus healthy controls, were significantly higher in the test with clinical-isolates antigen than the standard-equine-type strain (6.0 ± 2.6 vs 4.0 ± 1.7, respectively; P < .0001). ELISA with antigen from human source might be more proper diagnosis test.
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Affiliation(s)
- N Worasilchai
- Interdisciplinary Program, Medical Microbiology, Graduate school, Chulalongkorn University, Bangkok, Thailand
| | - A Leelahavanichkul
- Division of Immunology, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Division of Nephrology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - N Permpalung
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina, USA
| | - C Kuityo
- Interdisciplinary Program, Medical Microbiology, Graduate school, Chulalongkorn University, Bangkok, Thailand
| | - T Phaisanchatchawan
- Interdisciplinary Program, Medical Microbiology, Graduate school, Chulalongkorn University, Bangkok, Thailand
| | - T Palaga
- Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - R Reantragoon
- Division of Immunology, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Center of Excellence in Immunology and Immune-mediated diseases, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - A Chindamporn
- Division of Mycology, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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Hasika R, Lalitha P, Radhakrishnan N, Rameshkumar G, Prajna NV, Srinivasan M. Pythium keratitis in South India: Incidence, clinical profile, management, and treatment recommendation. Indian J Ophthalmol 2019; 67:42-47. [PMID: 30574890 PMCID: PMC6324135 DOI: 10.4103/ijo.ijo_445_18] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To study the demographic profile, clinical features, treatment outcome, and ocular morbidity of microbiologically proven Pythium keratitis in South India. METHODS A retrospective analysis of clinical records of microbiologically proven Pythium keratitis at a tertiary eye care referral center in South India from January 2016 to November 2017 was performed. Demographic details, predisposing risk factors, microbiological investigations, clinical course, and visual outcome were analyzed. RESULTS Seventy-one patients with microbiologically proven Pythium keratitis were identified. The mean age was 44(±18.2) years with an increase in male preponderance and 50% were farmers. Duration of delay at time of presentation to the hospital was a mean of 14(±7.2) days. The visual acuity at baseline ranged from 6/6 to no light perception (median 2.1 logMAR). A combination of 5% natamycin and 1% voriconazole was given to 42% patients, and natamycin alone was given to 39.4% patients. 1% itraconazole eye drops alone was initiated in 7 (10%) patients and 3 among this group responded. Therapeutic keratoplasty (TPK) was performed in 48 (67.6%) patients. None of the primary grafts remained clear after a period of 1 month. Twenty-six eyes (54.2%) had graft reinfection and all these eyes either developed anterior staphyloma (4) or were eviscerated (3) and 13 eyes became phthisical. The remaining 22 patients who had TPK resulted in failed graft. Among these, re-grafts were performed in 6 patients, of which 5 were doing well at the last follow-up. CONCLUSION We report a large series of patients with Pythium keratitis. Promoting early and differential diagnosis, awareness of clinicians and specific treatment options are needed for this devastating corneal disease.
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Affiliation(s)
- Ravula Hasika
- Department of Cornea and Refractive Surgery Services, Aravind Eye Hospital, Madurai, Tamil Nadu, India
| | - Prajna Lalitha
- Department of Ocular Microbiology, Aravind Eye Hospital, Madurai, Tamil Nadu, India,Correspondence to: Dr. Prajna Lalitha, Department of Ocular Microbiology, Aravind Eye Hospital, Madurai - 625 020, Tamil Nadu, India. E-mail:
| | - Naveen Radhakrishnan
- Department of Cornea and Refractive Surgery Services, Aravind Eye Hospital, Madurai, Tamil Nadu, India
| | | | - N Venkatesh Prajna
- Department of Cornea and Refractive Surgery Services, Aravind Eye Hospital, Madurai, Tamil Nadu, India
| | - Muthiah Srinivasan
- Department of Cornea and Refractive Surgery Services, Aravind Eye Hospital, Madurai, Tamil Nadu, India
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Agarwal S, Iyer G, Srinivasan B, Benurwar S, Agarwal M, Narayanan N, Lakshmipathy M, Radhika N, Rajagopal R, Krishnakumar S, K LT. Clinical profile, risk factors and outcome of medical, surgical and adjunct interventions in patients with Pythium insidiosum keratitis. Br J Ophthalmol 2018; 103:296-300. [PMID: 30206158 DOI: 10.1136/bjophthalmol-2017-311804] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 06/05/2018] [Accepted: 08/20/2018] [Indexed: 11/04/2022]
Abstract
PURPOSE To report clinical profile and compare management options for Pythium keratitis. METHOD Retrospective interventional study of 46 patients diagnosed as Pythium keratitis by PCR DNA sequencing from January 2014 to July 2017. Interventions were categorised into medical management (MM) (topical azithromycin and linezolid with oral azithromycin at presentation), surgery (S) (therapeutic penetrating keratoplasty, TPK), surgical adjunct (SA) (cryotherapy±alcohol with TPK) and medical adjunct (MA) (MM after TPK). RESULTS Primary treatment included MM (1 eye), SA (3 eyes) and S (42 eyes). Recurrence occurred in 27/43 eyes (MM+S group). Second surgery (S) was required in 11 eyes (TPK-2), with additional procedures (SA) in 10 eyes and evisceration in five eyes. 8/43 eyes received MA after TPK-1. One eye required TPK-3. Recurrence occured in all eyes that received MA (100%) and in 28 of 54 TPKs (51.8%) (TPK 1+2+3) in 42 eyes. Recurrence was noted in 1/14 (7.1%) that underwent SA. CONCLUSION The currently available and recommended treatment for Pythium keratitis is surgical by means of a TPK and in worse cases evisceration. In our study, MM/MA measures showed no benefit with recurrence or worsening of infection requiring resurgery. Almost 50% of TPKs had a recurrence requiring resurgery. However, adjunctive procedures during TPK appear to have additional benefit with low risk of recurrence and could be included as routine care.
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Affiliation(s)
- Shweta Agarwal
- CJ Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Chennai, Tamil Nadu, India
| | - Geetha Iyer
- CJ Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Chennai, Tamil Nadu, India
| | - Bhaskar Srinivasan
- CJ Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Chennai, Tamil Nadu, India
| | - Saket Benurwar
- CJ Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Chennai, Tamil Nadu, India
| | - Mamta Agarwal
- CJ Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Chennai, Tamil Nadu, India
| | - Niveditha Narayanan
- CJ Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Chennai, Tamil Nadu, India
| | - Meena Lakshmipathy
- CJ Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Chennai, Tamil Nadu, India
| | - N Radhika
- CJ Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Chennai, Tamil Nadu, India
| | - Rama Rajagopal
- CJ Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Chennai, Tamil Nadu, India
| | - S Krishnakumar
- L&T Ophthalmic Pathology Department, Vision Research Foundation, Chennai, Tamil Nadu, India
| | - Lily Therese K
- L&T Microbiology Research Centre, Vision Research Foundation, Chennai, Tamil Nadu, India
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Monitoring Anti-Pythium insidiosum IgG Antibodies and (1→3)-β-d-Glucan in Vascular Pythiosis. J Clin Microbiol 2018; 56:JCM.00610-18. [PMID: 29848566 DOI: 10.1128/jcm.00610-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 05/22/2018] [Indexed: 11/20/2022] Open
Abstract
Despite aggressive treatment, vascular pythiosis has a mortality rate of 40%. This is due to delays in diagnosis and a lack of effective monitoring tools. To overcome this drawback, serum beta-d-glucan (BG) and P. insidiosum-specific antibody (Pi-Ab) were examined as potential monitoring markers in vascular pythiosis. A prospective cohort study of vascular pythiosis patients was carried out from January 2010 to July 2016. Clinical information and blood samples were collected and evaluated by the BG and Pi-Ab assays. Linear mixed-effect models were used to compare BG and Pi-Ab levels. The in vitro susceptibility test was performed with all P. insidiosum isolates from culture-positive cases. A total of 50 patients were enrolled: 45 survived and 5 died during follow-up. The survivors had a significantly shorter time to medical care (P < 0.0001) and a significantly shorter waiting time to the first surgery (P < 0.0001). There were no differences in BG levels among the groups at diagnosis (P = 0.33); however, BG levels among survivors were significantly lower than those of the deceased group at 0.5 months (P < 0.0001) and became undetectable after 3 months. Survivors were able to maintain an enzyme-linked immunosorbent assay (ELISA) value (EV) of Pi-Ab above 8, whereas the EV among deceased patients was less than 4. In vitro susceptibility results revealed no synergistic effects between itraconazole and terbinafine. This study showed that BG and Pi-Ab are potentially valuable markers to monitor the disease after treatment initiation. An unchanged BG level at 2 weeks after surgery should prompt an evaluation for residual disease.
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Abstract
PURPOSE To investigate the role of in vivo confocal microscopy for detection of Pythium insidiosum keratitis. METHODS Medical records and confocal microscopy findings of 20 patients (21 eyes) with culture- or polymerase chain reaction-proven P. insidiosum keratitis diagnosed at the Khon Kaen University Eye Center from January 2009 to December 2015 were retrospectively reviewed. Confocal microscopy was performed using Nidek ConfoScan 4. The images from 21 eyes with P. insidiosum keratitis and 4 other fungal keratitides were analyzed visually for morphology of the hyphae and special characteristics that would enable physicians to distinguish P. insidiosum keratitis from other fungal keratitides. RESULTS A total of 21 eyes of 20 patients were included in the study. Fourteen (70%) were men, and 6 (30%) were women. In vivo confocal microscopy was able to identify hyphae in 20 of 21 eyes (95%). Beaded string-like hyperreflective branching structures with mean branching angles at 78.6 degrees or thin hyperreflective long lines were found in confocal microscopy findings of P. insidiosum keratitis. The diameter of the hyphae varied from 1.5 to 7.5 μm. CONCLUSIONS P. insidiosum keratitis is a severe progressive infectious corneal disease that causes vision loss in most patients. Confocal microscopy may provide rapid in vivo visualization of P. insidiosum hyphae in corneal tissues, but it cannot distinguish P. insidiosum from other fungal keratitides. Culture identification with zoospore induction or polymerase chain reaction remains the most reliable means to confirm the diagnosis of P. insidiosum keratitis.
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Agarwal S, Iyer G, Srinivasan B, Agarwal M, Panchalam Sampath Kumar S, Therese LK. Clinical profile of pythium keratitis: perioperative measures to reduce risk of recurrence. Br J Ophthalmol 2017; 102:153-157. [PMID: 28903964 DOI: 10.1136/bjophthalmol-2017-310604] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 08/21/2017] [Accepted: 08/25/2017] [Indexed: 11/03/2022]
Abstract
PURPOSE To report the clinical profile and role of perioperative adjunctive measures to reduce the risk of recurrence in Pythium insidiosum keratitis. METHODS Retrospective analysis of 10 eyes of 10 patients with P. insidiosum keratitis. Diagnosis was confirmed by PCR DNA sequencing. RESULTS 7out of 10 patients were from urban locales, and none had any obvious history of injury with vegetative matter and were being treated for fungal keratitis. 6 eyes presented with central full thickness infiltrates with subepithelial and superficial stromal infiltrates radiating in a reticular pattern. Corneal scraping in all eyes revealed sparsely septate fungal-like filaments on potassium hydroxide/Calcofluor. All eyes underwent the first therapeutic penetrating keratoplasty (TPK) based on worsening or non-responsiveness of clinical features to the antifungal regimen. Recurrence was noted in 7 out of 10 eyes of which 2 eyes underwent evisceration. Of the six eyes that underwent cryotherapy following confirmation of microbiological diagnosis of Pythium (along with primary TPK-1, with re-TPK-5), only one eye had a recurrence and had to be eviscerated. Of the two eyes that did not undergo cryotherapy during re-TPK, following microbiological diagnosis, one eye had a recurrence and had to be eviscerated. In two eyes with adjoining scleritis, the host bed was swabbed using absolute alcohol of which one eye was salvaged. CONCLUSION This series highlights the need to be aware of this entity in the management of refractory fungal keratitis. It also brings to fore the adjunctive measures that could have a beneficial role in the management of pythium keratitis.
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Affiliation(s)
- Shweta Agarwal
- CJ Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Geetha Iyer
- CJ Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Bhaskar Srinivasan
- CJ Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Mamta Agarwal
- CJ Shah Cornea Services, Dr G Sitalakshmi Memorial Clinic for Ocular Surface Disorders, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | | | - Lily K Therese
- L&T Microbiology Research Centre, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
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He H, Liu H, Chen X, Wu J, He M, Zhong X. Diagnosis and Treatment of Pythium Insidiosum Corneal Ulcer in a Chinese Child: A Case Report and Literature Review. AMERICAN JOURNAL OF CASE REPORTS 2016; 17:982-988. [PMID: 28025573 PMCID: PMC5207016 DOI: 10.12659/ajcr.901158] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Patient: Male, 7 Final Diagnosis: Pythium insidiosum Symptoms: Painful vision loss • red eye Medication:— Clinical Procedure: Application of multiple antifungal medicines followed by the penetrating keratoplasty Specialty: Ophthalmology
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Affiliation(s)
- Hong He
- Hainan Eye Hospital and Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Haikou, Hainan, China (mainland)
| | - Hongshan Liu
- Hainan Eye Hospital and Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Haikou, Hainan, China (mainland)
| | - Xiaolian Chen
- Hainan Eye Hospital and Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Haikou, Hainan, China (mainland)
| | - Jiaochan Wu
- Hainan Eye Hospital and Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Haikou, Hainan, China (mainland)
| | - Miao He
- Zhongshan Ophthalmic Center and State Key Laboratory of Ophthalmology, Sun Yat-sen Universityq, Guangzhou, Guangdong, China (mainland)
| | - Xingwu Zhong
- Hainan Eye Hospital and Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Haikou, Hainan, China (mainland).,Zhongshan Ophthalmic Center and State Key Laboratory of Ophthalmology, Sun Yat-sen Universityq, Guangzhou, Guangdong, China (mainland)
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Intaramat A, Sornprachum T, Chantrathonkul B, Chaisuriya P, Lohnoo T, Yingyong W, Jongruja N, Kumsang Y, Sandee A, Chaiprasert A, Banyong R, Santurio JM, Grooters AM, Ratanabanangkoon K, Krajaejun T. Protein A/G-based immunochromatographic test for serodiagnosis of pythiosis in human and animal subjects from Asia and Americas. Med Mycol 2016; 54:641-7. [PMID: 27118800 DOI: 10.1093/mmy/myw018] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Accepted: 02/24/2016] [Indexed: 11/13/2022] Open
Abstract
Pythiosis is a life-threatening infectious disease of both humans and animals living in Asia, Americas, Africa, and parts of Australia and New Zealand. The etiologic pathogen is the fungus-like organism Pythium insidiosum The disease has high mortality and morbidity rates. Use of antifungal drugs are ineffective against P. insidiosum, leaving radical surgery the main treatment option. Prompt treatment leads to better prognosis of affected individuals, and could be achieved by early and accurate diagnosis. Since pythiosis has been increasingly reported worldwide, there is a need for a rapid, user-friendly, and efficient test that facilitates the diagnosis of the disease. This study aims to develop an immunochromatographic test (ICT), using the bacterial protein A/G, to detect anti-P. insidiosum IgGs in humans and animals, and compare its diagnostic performance with the established ELISA. Eighty-five serum samples from 28 patients, 24 dogs, 12 horses, 12 rabbits, and 9 cattle with pythiosis, and 143 serum samples from 80 human and 63 animal subjects in a healthy condition, with thalassemia, or with other fungal infections, were recruited for assay evaluation. Detection specificities of ELISA and ICT were 100.0%. While the detection sensitivity of ELISA was 98.8%, that of ICT was 90.6%. Most pythiosis sera, that were falsely read negative by ICT, were weakly positive by ELISA. In conclusion, a protein A/G-based ICT is a rapid, user-friendly, and efficient assay for serodiagnosis of pythiosis in humans and animals. Compared to ELISA, ICT has an equivalent detection specificity and a slightly lower detection sensitivity.
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Affiliation(s)
- Akarin Intaramat
- Laboratory of Immunology, Chulabhorn Research Institute, Bangkok, Thailand
| | | | | | - Papada Chaisuriya
- Laboratory of Immunology, Chulabhorn Research Institute, Bangkok, Thailand
| | - Tassanee Lohnoo
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Wanta Yingyong
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Nujarin Jongruja
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Yothin Kumsang
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Alisa Sandee
- Laboratory of Immunology, Chulabhorn Research Institute, Bangkok, Thailand
| | - Angkana Chaiprasert
- Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Ramrada Banyong
- Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Janio M Santurio
- Departamento de Microbiologia e Parasitologia, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Amy M Grooters
- Department of Veterinary Clinical Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Kavi Ratanabanangkoon
- Laboratory of Immunology, Chulabhorn Research Institute, Bangkok, Thailand Chulabhorn Graduate Institute, Bangkok, Thailand
| | - Theerapong Krajaejun
- Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
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Pythium insidiosum keratitis: clinical profile and role of DNA sequencing and zoospore formation in diagnosis. Cornea 2015; 34:438-42. [PMID: 25738236 DOI: 10.1097/ico.0000000000000349] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To report the molecular and microbiological diagnosis and clinical profile of 13 patients with Pythium insidiosum keratitis. METHODS Phase 1 of the study consisted of DNA sequencing of the ITS region of the rDNA of 162 stocked morphologically unidentified nonconsecutive fungal isolates from corneal scraping of patients with keratitis (2010-2012). Blast and phylogenetic analyses of the sequences showed 9 to be P. insidiosum. A retrospective review of archived photographs of colony and direct microscopy of corneal scrapings and clinical records of the cases were performed. Phase 2 began in 2014, in which a simple method of zoospore formation was used for fungal colonies resembling those of P. insidiosum followed by DNA sequencing. RESULTS The prevalence of P. insidiosum among unidentified fungal isolates from keratitis was 9/162 (5.5%) in phase 1. In phase 2, 4/102 cases (3.9%) of fungal keratitis were identified as P. insidiosum (January-February, 2014). Phylogenetic analysis of all 13 fungal isolates confirmed the identification of P. insidiosum. Corneal infiltrates exhibited hyphate edges, tentacle-like extensions, and dot-like infiltrates surrounding the main infiltrate. Response to topical 5% natamycin eye drops with or without oral antifungals was poor (penetrating keratoplasty: 9 and evisceration: 2) with a mean follow-up period of 82 days. CONCLUSIONS P. insidiosum keratitis needs to be considered in the differential diagnosis of severe fungal keratitis. It can be identified using the zoospore formation method and confirmed by ITS DNA sequencing. Lack of response to currently used antifungal drugs calls for evaluation of newer drugs for medical therapy and consideration for early penetrating keratoplasty.
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Lelievre L, Borderie V, Garcia-Hermoso D, Brignier AC, Sterkers M, Chaumeil C, Lortholary O, Lanternier F. Imported pythium insidiosum keratitis after a swim in Thailand by a contact lens-wearing traveler. Am J Trop Med Hyg 2014; 92:270-3. [PMID: 25535313 DOI: 10.4269/ajtmh.14-0380] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A 30-year-old woman with a history of contact lens wear and exposure to swimming pool water in Thailand presented with a non-responsive, progressive corneal ulcer of the right eye. Confocal microscopy evidenced septate linear branching structures, raising suspicion of fungal keratitis. She was promptly treated with topical antibiotics and both topical and intravenous caspofungin plus voriconazole. Worsening of the clinical picture after 1 month of intensive medical therapy led to a large therapeutic penetrating keratoplasty being performed. Corneal cultures grew a mold-like organism, which was identified by sequencing as Pythium insidiosum, an aquatic oomycete. After 4 years of follow-up, the graft exhibits no infection relapse, but graft transparency has been lost after two rejection episodes. Keratoplasty combined with antifungal treatment may offer a cure to P. insidiosum keratitis, although long-term preservation of corneal transparency is difficult to obtain.
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Affiliation(s)
- Lucie Lelievre
- Université Paris-Descartes, Centre d'Infectiologie Necker-Pasteur, IHU Imagine, Hôpital Necker-Enfants Malades, APHP, Paris, France; Fédération de Pathologie Infectieuse Oculaire, Centre de Recherche Institut de la Vision, UMR S 968 Inserm/UPMC/CHNO des Quinze-Vingts, Paris, France; Institut Pasteur, Centre National de Référence Mycoses Invasives et Antifongiques, CNRS URA3012, Paris, France; Service de Microbiologie, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France
| | - Vincent Borderie
- Université Paris-Descartes, Centre d'Infectiologie Necker-Pasteur, IHU Imagine, Hôpital Necker-Enfants Malades, APHP, Paris, France; Fédération de Pathologie Infectieuse Oculaire, Centre de Recherche Institut de la Vision, UMR S 968 Inserm/UPMC/CHNO des Quinze-Vingts, Paris, France; Institut Pasteur, Centre National de Référence Mycoses Invasives et Antifongiques, CNRS URA3012, Paris, France; Service de Microbiologie, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France
| | - Dea Garcia-Hermoso
- Université Paris-Descartes, Centre d'Infectiologie Necker-Pasteur, IHU Imagine, Hôpital Necker-Enfants Malades, APHP, Paris, France; Fédération de Pathologie Infectieuse Oculaire, Centre de Recherche Institut de la Vision, UMR S 968 Inserm/UPMC/CHNO des Quinze-Vingts, Paris, France; Institut Pasteur, Centre National de Référence Mycoses Invasives et Antifongiques, CNRS URA3012, Paris, France; Service de Microbiologie, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France
| | - Anne C Brignier
- Université Paris-Descartes, Centre d'Infectiologie Necker-Pasteur, IHU Imagine, Hôpital Necker-Enfants Malades, APHP, Paris, France; Fédération de Pathologie Infectieuse Oculaire, Centre de Recherche Institut de la Vision, UMR S 968 Inserm/UPMC/CHNO des Quinze-Vingts, Paris, France; Institut Pasteur, Centre National de Référence Mycoses Invasives et Antifongiques, CNRS URA3012, Paris, France; Service de Microbiologie, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France
| | - Margaret Sterkers
- Université Paris-Descartes, Centre d'Infectiologie Necker-Pasteur, IHU Imagine, Hôpital Necker-Enfants Malades, APHP, Paris, France; Fédération de Pathologie Infectieuse Oculaire, Centre de Recherche Institut de la Vision, UMR S 968 Inserm/UPMC/CHNO des Quinze-Vingts, Paris, France; Institut Pasteur, Centre National de Référence Mycoses Invasives et Antifongiques, CNRS URA3012, Paris, France; Service de Microbiologie, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France
| | - Christine Chaumeil
- Université Paris-Descartes, Centre d'Infectiologie Necker-Pasteur, IHU Imagine, Hôpital Necker-Enfants Malades, APHP, Paris, France; Fédération de Pathologie Infectieuse Oculaire, Centre de Recherche Institut de la Vision, UMR S 968 Inserm/UPMC/CHNO des Quinze-Vingts, Paris, France; Institut Pasteur, Centre National de Référence Mycoses Invasives et Antifongiques, CNRS URA3012, Paris, France; Service de Microbiologie, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France
| | - Olivier Lortholary
- Université Paris-Descartes, Centre d'Infectiologie Necker-Pasteur, IHU Imagine, Hôpital Necker-Enfants Malades, APHP, Paris, France; Fédération de Pathologie Infectieuse Oculaire, Centre de Recherche Institut de la Vision, UMR S 968 Inserm/UPMC/CHNO des Quinze-Vingts, Paris, France; Institut Pasteur, Centre National de Référence Mycoses Invasives et Antifongiques, CNRS URA3012, Paris, France; Service de Microbiologie, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France
| | - Fanny Lanternier
- Université Paris-Descartes, Centre d'Infectiologie Necker-Pasteur, IHU Imagine, Hôpital Necker-Enfants Malades, APHP, Paris, France; Fédération de Pathologie Infectieuse Oculaire, Centre de Recherche Institut de la Vision, UMR S 968 Inserm/UPMC/CHNO des Quinze-Vingts, Paris, France; Institut Pasteur, Centre National de Référence Mycoses Invasives et Antifongiques, CNRS URA3012, Paris, France; Service de Microbiologie, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France
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Keratitis caused by Pythium insidiosum in an immunosuppressed patient with Crohn's disease. Clin Gastroenterol Hepatol 2014; 12:A21-2. [PMID: 24793025 DOI: 10.1016/j.cgh.2014.04.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 04/21/2014] [Indexed: 02/07/2023]
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Abstract
PURPOSE To describe typical clinical and laboratory characteristics of severe fungal keratitis caused by Pythium insidiosum during the rainy season in Northeast Thailand and to report the efficacy of P. insidiosum vaccine in the treatment of Pythium keratitis. METHODS A series of hospital-based consecutive cases of Pythium keratitis were diagnosed and treated at Srinagarind Hospital (Khon Kaen University, Khon Kaen, Thailand). The clinical presentations, diagnostic tests, and management are described. RESULTS Severe fungal keratitis caused by P. insidiosum was diagnosed in 5 eyes of 4 patients between May 2009 and July 2009. All cases had a history of fungal keratitis after being exposed to contaminated water. Upon slit-lamp examination, subepithelial and superficial stromal opacities were observed in a reticular pattern in all cases. Pythium insidiosum was identified and confirmed by both microbiological culture and polymerase chain reaction. Clinical worsening was detected after conventional treatment with antifungal agents. Therapeutic penetrating keratoplasty with either donor cornea or scleral graft was performed together with topical antifungal administration and P. insidiosum vaccination. Subsequent evisceration was performed in 1 eye. CONCLUSIONS An outbreak of Pythium keratitis in Northeast Thailand was reported. Distinctive clinical features are a suggestive clue for early diagnosis. Combination treatment including topical antifungal agents, radical surgery, and P. insidiosum vaccine may be considered for the management of Pythium keratitis.
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Abstract
This is a report of a Lagenidium sp. in a Thai patient who was diagnosed with severe keratitis that was unresponsive to antibacterial and antifungal drugs. Examination of a corneal biopsy specimen confirmed the presence of aseptate hyphae. The internal transcribed spacer DNA sequence of the strain isolated showed 97% identity with Lagenidium giganteum and other Lagenidium species.
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Barequet IS, Lavinsky F, Rosner M. Long-term follow-up after successful treatment of Pythium insidiosum keratitis in Israel. Semin Ophthalmol 2013; 28:247-50. [PMID: 23627654 DOI: 10.3109/08820538.2013.788676] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The purpose of this project is to report a case of severe Pythium insidiosum keratitis confirmed by polymerase chain reaction (PCR), and its long-term cure after therapeutic penetrating keratoplasty. A 24-year-old woman with a history of contact lens wear and exposure to swimming pool water presented with a severe corneal abscess. She was treated with intensive fortified topical antibiotics and natamycin with limited response. Initial cultures suggested the presence of a septate mold, unclearly identified; therefore, both topical and intravenous voriconazole were administered. Despite the above treatment, there was worsening of the clinical picture. PCR assay revealed homology to Pythium insidiosum. Promptly, the patient underwent a large therapeutic penetrating keratoplasty. After five years of follow-up, the graft exhibits neither signs of rejection nor any recurrence of infection. We conclude that prompt identification of Pythium insidiosum keratitis and aggressive treatment by therapeutic penetrating keratoplasty may offer a cure to this disease.
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Affiliation(s)
- Irina S Barequet
- Goldschleger Eye Institute, Sheba Medical Center, Sackler School of Medicine, Tel-Hashomer, Israel.
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Del Castillo-Jiménez MC, Baptista-Díaz N, Montero J, Pascual A. [Pythium insidiosum ocular infection]. Enferm Infecc Microbiol Clin 2012; 31:118-9. [PMID: 22981326 DOI: 10.1016/j.eimc.2012.07.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 07/19/2012] [Accepted: 07/19/2012] [Indexed: 10/27/2022]
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Slavin MA, Chakrabarti A. Opportunistic fungal infections in the Asia-Pacific region. Med Mycol 2012; 50:18-25. [DOI: 10.3109/13693786.2011.602989] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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Abstract
PURPOSE OF REVIEW The purpose of this review is to provide an update of peer-reviewed literature published over the previous 2 years on various aspects of therapeutic keratoplasty. RECENT FINDINGS Therapeutic keratoplasty has a definitive role in the management of progressive microbial keratitis refractory to medical therapy. The primary aim of the procedure is to eliminate the infectious disease process and establish the integrity of the globe. This procedure offers a microbiological cure rate of up to 100% in bacterial keratitis; recurrence of infection remains a concern following fungal infections and Acanthamoeba keratitis. Newer techniques like corneal debulking allow maximal preservation of the iris tissue in cases of perforated corneal ulcers. Lamellar procedures are emerging as promising alternatives to the full thickness graft in cases of infectious keratitis sparing the Descemet's membrane. In addition to adept intraoperative skills, intensive postoperative treatment and meticulous follow-up are pivotal to ensure success of a therapeutic graft. SUMMARY Therapeutic keratoplasty is a challenging procedure and is associated with a poor prognosis for graft survival as compared with the optical grafts. The recent advances in lamellar keratoplasty and antimicrobial therapy contribute to the success in terms of microbiological cure and improved visual outcomes.
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