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Ong HS, Sharma N, Phee LM, Mehta JS. Atypical microbial keratitis. Ocul Surf 2023; 28:424-439. [PMID: 34768003 DOI: 10.1016/j.jtos.2021.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/29/2021] [Accepted: 11/01/2021] [Indexed: 01/16/2023]
Abstract
Atypical microbial keratitis refers to corneal infections caused by micro-organisms not commonly encountered in clinical practice. Unlike infections caused by common bacteria, cases of atypical microbial keratitis are often associated with worse clinical outcomes and visual prognosis. This is due to the challenges in the identification of causative organisms with standard diagnostic techniques, resulting in delays in the initiation of appropriate therapies. Furthermore, due to the comparatively lower incidence of atypical microbial keratitis, there is limited literature on effective management strategies for some of these difficult to manage corneal infections. This review highlights the current management and available evidence of atypical microbial keratitis, focusing on atypical mycobacteria keratitis, nocardia keratitis, achromobacter keratitis, and pythium keratitis. It will also describe the management of two uncommonly encountered conditions, infectious crystalline keratopathy and post-refractive infectious keratitis. This review can be used as a guide for clinicians managing patients with such challenging corneal infections.
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Affiliation(s)
- Hon Shing Ong
- Corneal and External Diseases Department, Singapore National Eye Centre, Singapore; Tissue Engineering and Cell Therapy Department, Singapore Eye Research Institute, Singapore; Department of Ophthalmology and Visual Science, Duke-National University of Singapore (NUS) Graduate Medical School, Singapore.
| | - Namrata Sharma
- Department of Ophthalmology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Lynette M Phee
- Department of Pathology, Sengkang General Hospital, SingHealth, Singapore
| | - Jodhbir S Mehta
- Corneal and External Diseases Department, Singapore National Eye Centre, Singapore; Tissue Engineering and Cell Therapy Department, Singapore Eye Research Institute, Singapore; Department of Ophthalmology and Visual Science, Duke-National University of Singapore (NUS) Graduate Medical School, Singapore; School of Material Science & Engineering and School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore.
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Jara M, Holcomb K, Wang X, Goss EM, Machado G. The Potential Distribution of Pythium insidiosum in the Chincoteague National Wildlife Refuge, Virginia. Front Vet Sci 2021; 8:640339. [PMID: 33681336 PMCID: PMC7933582 DOI: 10.3389/fvets.2021.640339] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 01/27/2021] [Indexed: 02/06/2023] Open
Abstract
Pythium insidiosum is a widespread pathogen that causes pythiosis in mammals. Recent increase in cases reported in North America indicates a need to better understand the distribution and persistence of the pathogen in the environment. In this study, we reconstructed the distribution of P. insidiosum in the Chincoteague National Wildlife Refuge, located on Assateague Island, Virginia, and based on 136 environmental water samples collected between June and September of 2019. The Refuge hosts two grazing areas for horses, also known as the Chincoteague Ponies. In the past 3 years, 12 horses have succumbed to infection by P. insidiosum. Using an ecological niche model framework, we estimated and mapped suitable areas for P. insidiosum throughout the Refuge. We found P. insidiosum throughout much of the study area. Our results showed significant monthly variation in the predicted suitability, where the most influential environmental predictors were land-surface water and temperature. We found that June, July, and August were the months with the highest suitability for P. insidiosum across the Refuge, while December through March were less favorable months. Likewise, significant differences in suitability were observed between the two grazing areas. The suitability map provided here could also be used to make management decisions, such as monitoring horses for lesions during high risk months.
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Affiliation(s)
- Manuel Jara
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, United States
| | - Kevin Holcomb
- U.S. Fish & Wildlife Service, Chincoteague National Wildlife Refuge, Chincoteague, VA, United States
| | - Xuechun Wang
- Mount Vernon Northwestern Washington Research & Extension Center Mount Vernon, Mount Vernon, WA, United States
| | - Erica M Goss
- Mount Vernon Northwestern Washington Research & Extension Center Mount Vernon, Mount Vernon, WA, United States
| | - Gustavo Machado
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, United States
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Mar Htun Z, Laikul A, Pathomsakulwong W, Yurayart C, Lohnoo T, Yingyong W, Kumsang Y, Payattikul P, Sae-Chew P, Rujirawat T, Jaturapaktrarak C, Chongtrakool P, Krajaejun T. An initial survey of 150 horses from Thailand for anti-Pythium insidiosum antibodies. J Mycol Med 2020; 31:101085. [PMID: 33259982 DOI: 10.1016/j.mycmed.2020.101085] [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: 05/23/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Pythium insidiosum causes a life-threatening infection termed pythiosis in humans and other animals. The organism has been identified in tropical and subtropical environments worldwide. Since 1985, human pythiosis has been increasingly reported from Thailand. Seroprevalence studies estimated that 32,000 Thai people had been exposed to the pathogen. In 2018, the first animal pythiosis case in Thailand was diagnosed in a horse. Here, we investigated the seroprevalence of anti-P. insidiosum antibodies in the Thai equine population. MATERIALS AND METHODS We surveyed serum anti-P. insidiosum antibodies in 150 horses distributed across Thailand, using three established serological tests: enzyme-linked immunosorbent assay (ELISA), immunochromatographic test (ICT), and Western blot analysis. RESULTS ELISA detected the anti-P. insidiosum antibodies in three horses. ICT and Western blot confirmed the presence of the antibodies in one of the ELISA-positive horses. Based on one positive out of 150 horses tested, the seroprevalence of anti-P. insidiosum antibodies in the Thai equine population was 0.7%, which is markedly higher than that in the Thai human population (0.07%), but much lower than that in the Brazilian equine population (11.1%). CONCLUSION The seroprevalence of the anti-P. insidiosum antibodies in the equine population suggests a higher incidence of pythiosis in horses than in humans. The antibody surveillance reported by our group was undertaken to promote a better understanding of the epidemiology and host susceptibility of pythiosis in Thailand.
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Affiliation(s)
- Z Mar Htun
- Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand; Department of Microbiology, University of Medicine, Mandalay, Myanmar; Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - A Laikul
- Department of Large Animal and Wildlife Clinical Sciences, Faculty of Veterinary Medicine, Kasetsart University, Nakhon Pathom, Thailand
| | - W Pathomsakulwong
- Equine Clinic, Veterinary Teaching Hospital, Kasetsart University, Nakhon Pathom, Thailand
| | - C Yurayart
- Department of Microbiology and Immunology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
| | - T Lohnoo
- Faculty of Medicine, Research Center, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - W Yingyong
- Faculty of Medicine, Research Center, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Y Kumsang
- Faculty of Medicine, Research Center, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - P Payattikul
- Faculty of Medicine, Research Center, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - P Sae-Chew
- Faculty of Medicine, Research Center, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - T Rujirawat
- Faculty of Medicine, Research Center, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - C Jaturapaktrarak
- Faculty of Medicine, Research Center, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - P Chongtrakool
- Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
| | - T Krajaejun
- Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
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Jaturapaktrarak C, Payattikul P, Lohnoo T, Kumsang Y, Laikul A, Pathomsakulwong W, Yurayart C, Tonpitak W, Krajaejun T. Protein A/G-based enzyme-linked immunosorbent assay for detection of anti-Pythium insidiosum antibodies in human and animal subjects. BMC Res Notes 2020; 13:135. [PMID: 32143691 PMCID: PMC7059324 DOI: 10.1186/s13104-020-04981-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 02/26/2020] [Indexed: 12/03/2022] Open
Abstract
Objectives Pythiosis is a deadly infectious disease caused by Pythium insidiosum. Reports of both human and animal pythiosis are on the rise worldwide. Prognosis of the pythiosis patients relies on early diagnosis and prompt treatment. There are needs for an immunodiagnostic test that can detect the disease in both humans and animals. This study aims at reporting an optimized protocol for the development of a protein A/G-based enzyme-linked immunosorbent assay (ELISA) for the detection of anti-P. insidiosum antibody in multiple host species. Results A total of 25 pythiosis and 50 control sera, obtained from humans, horses, dogs, cats, and cows, were recruited for the assay development. With a proper ELISA cutoff point, all pythiosis sera can ultimately be distinguished from the control sera. The successfully-developed protein A/G-based ELISA can detect the anti-P. insidiosum antibodies in serum samples of both humans and animals. It is a versatile, feasible-to-develop, and functional immunodiagnostic assay for pythiosis.
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Affiliation(s)
- Chalisa Jaturapaktrarak
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.,Molecular Medicine Program, Multidisciplinary Unit, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Penpan Payattikul
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Tassanee Lohnoo
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Yothin Kumsang
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Aree Laikul
- Department of Large Animal and Wildlife Clinical Sciences, Faculty of Veterinary Medicine, Kasetsart University, Nakhon Pathom, Thailand
| | | | - Chompoonek Yurayart
- Department of Microbiology and Immunology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
| | - Walaiporn Tonpitak
- Department of Microbiology, Faculty of Veterinary Medicine, Mahanakorn University of Technology, Bangkok, Thailand
| | - Theerapong Krajaejun
- Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
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Human Pythiosis: Emergence of Fungal-Like Organism. Mycopathologia 2019; 185:801-812. [PMID: 31845178 DOI: 10.1007/s11046-019-00412-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 11/28/2019] [Indexed: 01/10/2023]
Abstract
Pythiosis is an emerging infectious disease caused by the aquatic oomycete Pythium insidiosum, a fungal-like organism. It is believed that P. insidiosum's zoospores, its infected form, play major role in pathogenesis. Vascular and ocular infections are the most common clinical manifestation in humans. It is difficult to establish the diagnosis given its relatively rarity and difficulty to distinguish P. insidiosum from other molds. Delay in diagnosis and treatment has been associated with poor outcomes. High index of suspicion is the key, particularly in thalassemia patients with arterial insufficiency and patients with fungal keratitis/endophthalmitis without improvement on antifungal therapy. Tissue culture and zoospore induction remain gold standard for diagnosis; however, DNA-based method should be performed simultaneously. The combination of radical surgery, antifungal agents, and immunotherapy has been recommended. It was previously believed that surgery with negative surgical margins was the essential to survive in vascular pythiosis; however, it was recently found that patients could have residual disease despite documented negative surgical margins as infected clot may be dislodged to proximal arterial sites prior to surgery. Serum β-D-glucan (BG) has been used to monitor disease response after treatment initiation in vascular pythiosis. A significant decrease in BG levels within 2 weeks after surgery is indicative of the absence of residual infection. Unfortunately, monitoring tools for ocular pythiosis are not yet available. Itraconazole plus terbinafine have generally been used in P. insidiosum-infected patients; however, antibacterial agents, including azithromycin and linezolid, have also been used with favorable outcomes in ocular disease. Recently, azithromycin or clarithromycin plus doxycyclin were used in two relapsed vascular pythiosis patients with good outcomes.
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Weiblen C, Zanette RA, Ribeiro TC, Pereira Dos Santos CE, Ianiski LB, Pereira DIB, Santurio JM, Botton SDA. Intradermal injection of Pythium insidiosum protein antigens for improved diagnosis and treatment of pythiosis in an experimental model. Med Mycol 2019; 57:807-812. [PMID: 30260397 DOI: 10.1093/mmy/myy078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/08/2018] [Accepted: 08/27/2018] [Indexed: 11/14/2022] Open
Abstract
The oomycetous pathogen Pythium insidiosum is the causative agent of pythiosis, a life-threatening disease that affects animals and humans. This infectious disease is difficult to treat, and early and accurate diagnosis is critical for effective treatment. In this sense, this study aimed to evaluate the intradermal (ID) injection of P. insidiosum protein antigens (PiPA) for the diagnosis and treatment of pythiosis using an experimental model. For diagnostic purposes, PiPA were injected by the ID route in the following groups of rabbits: (a) control; (b) previously immunized with PiPA injected by the subcutaneous (SC) route; and (c) infected with P. insidiosum zoospores. For treatment purposes, rabbits with pythiosis were also treated with PiPA by the ID or SC routes. Mean induration sizes were different at 24 h and 72 h readings when compared to the control group. Sensitivity of the protocol was 100% at 24 h and 80% at 72 h, with 100% specificity in both readings. PiPA treatment using ID or SC routes did not result in significant differences in lesion sizes and cure rates; however, serum levels of interferon-gamma were higher in SC route. This study demonstrates the applicability of PiPA ID for diagnosis and treatment of pythiosis in an experimental model.
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Affiliation(s)
- Carla Weiblen
- Universidade Federal de Santa Maria (UFSM). aDepartamento de Medicina Veterinária Preventiva (DMVP)/ Programa de Pós Graduação em Medicina Veterinária (PPGMV)/ Centro de Ciências Rurais (CCR). bDepartamento de Microbiologia e Parasitologia (Demip)/Centro de Ciências da Saúde (CCS)
| | - Régis Adriel Zanette
- Universidade Federal do Rio Grande do Sul (UFRGS), Programa de Pós-Graduação em Ciências Biológicas: Farmacologia e Terapêutica
| | - Tatiana Corrêa Ribeiro
- Universidade Federal de Santa Maria (UFSM). aDepartamento de Medicina Veterinária Preventiva (DMVP)/ Programa de Pós Graduação em Medicina Veterinária (PPGMV)/ Centro de Ciências Rurais (CCR). bDepartamento de Microbiologia e Parasitologia (Demip)/Centro de Ciências da Saúde (CCS)
| | | | - Lara Baccarin Ianiski
- Universidade Federal de Santa Maria (UFSM). aDepartamento de Medicina Veterinária Preventiva (DMVP)/ Programa de Pós Graduação em Medicina Veterinária (PPGMV)/ Centro de Ciências Rurais (CCR). bDepartamento de Microbiologia e Parasitologia (Demip)/Centro de Ciências da Saúde (CCS)
| | | | - Janio Morais Santurio
- Universidade Federal de Santa Maria (UFSM). aDepartamento de Medicina Veterinária Preventiva (DMVP)/ Programa de Pós Graduação em Medicina Veterinária (PPGMV)/ Centro de Ciências Rurais (CCR). bDepartamento de Microbiologia e Parasitologia (Demip)/Centro de Ciências da Saúde (CCS)
| | - Sônia de Avila Botton
- Universidade Federal de Santa Maria (UFSM). aDepartamento de Medicina Veterinária Preventiva (DMVP)/ Programa de Pós Graduação em Medicina Veterinária (PPGMV)/ Centro de Ciências Rurais (CCR). bDepartamento de Microbiologia e Parasitologia (Demip)/Centro de Ciências da Saúde (CCS)
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