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Peano A, Min ARM, Fondati A, Romano E, Brachelente C, Porcellato I, Amore A, Pasquetti M. Cutaneous Pythiosis in 2 Dogs, Italy. Emerg Infect Dis 2023; 29:1447-1450. [PMID: 37347828 PMCID: PMC10310393 DOI: 10.3201/eid2907.230320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2023] Open
Abstract
We report cutaneous pythiosis in 2 dogs in Italy that had recurrent exposure to the same freshwater habitat. Phylogenetic analysis placed the isolates within Pythium insidiosum complex cluster IV, corresponding to P. periculosum. In Italy, pythiosis should be considered in differential diagnoses by human and veterinary health professionals.
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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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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. Curr Ophthalmol Rep 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] [What about the content of this article? (0)] [Affiliation(s)] [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] [What about the content of this article? (0)] [Affiliation(s)] [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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Perkins MJ, Rosario DJ, Wickes BL, Krajaejun T, Sherwood JE, Mody RM. Severe skin and soft tissue pythiosis acquired in a hot sp. Travel Med Infect Dis 2022. [DOI: 10.1016/j.tmaid.2022.102349] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [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] [What about the content of this article? (0)] [Affiliation(s)] [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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Miraglia BM, Mendoza L, Rammohan R, Vilela L, Vilela C, Vilela G, Huebner M, Mani R, Vilela R. Pythium insidiosum complex hides a cryptic novel species: Pythium periculosum. Fungal Biol 2022; 126:366-374. [DOI: 10.1016/j.funbio.2022.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/14/2022] [Indexed: 11/28/2022]
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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: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Hou H, Wang Y, Tian L, Wang F, Sun Z, Chen Z. Pythium insidiosum keratitis reported in China, raising the alertness to this fungus-like infection: a case series. J Med Case Rep 2021; 15:619. [PMID: 34915928 DOI: 10.1186/s13256-021-03189-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 11/08/2021] [Indexed: 11/24/2022] Open
Abstract
Background The objective of this study is to report typical clinical and laboratory characteristics of three cases of keratitis caused by Pythium insidiosum in China. Case presentation Three Chinese patients of Han nationality diagnosed with Pythium keratitis from 2017 to 2019 were included. One 45-year-old female and one 55-year-old male were exposed to river water, and one 51-year-old female was burned by ash in the eyes. All of them are of Han ethnicity. Upon slit-lamp examination, subepithelial and superficial stromal opacities were observed in a reticular pattern. After conventional treatment with antifungal agents, the clinical status worsened and therapeutic penetrating keratoplasty was performed. Unfortunately, enucleation was performed to remove all infected tissue and relieve pain. Pythium insidiosum was identified in culture and confirmed by internal transcribed spacer ribosomal RNA gene sequencing analysis. Following the systemic and local antibiotic regimens, the patients were cured ultimately and no regression of infection was observed. Conclusions It is significant for ophthalmologists and microbiologist to be alert to this eye-threatening infection, especially in patients who are resistant to antifungal treatments and with water-related exposure.
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Souto EPF, Maia LA, Neto EGM, Kommers GD, Junior FG, Riet-Correa F, Galiza GJN, Dantas AFM. Pythiosis in Equidae in Northeastern Brazil: 1985-2020. J Equine Vet Sci 2021; 105:103726. [PMID: 34607686 DOI: 10.1016/j.jevs.2021.103726] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/01/2021] [Accepted: 08/02/2021] [Indexed: 10/20/2022]
Abstract
The epidemiologic, clinical, pathologic, microbiological and immunohistochemical findings of pythiosis in equidae in northeastern Brazil are described. From January 1985 to December 2020 the Laboratory of Animal Pathology of the Federal University of Campina Grande received 1,331 tissue samples of equidae, 202 (15.17%) of which were diagnosed as pythiosis. Equidae of both sexes with ages varying from 4 months to 25 years were affected. Most animals were mixed breed (79.7%) and reared in an extensive system (73.26%). The disease occurred throughout the year but the highest incidence (70.29%) was noted after the rainy season. The clinical course was always chronic. The lesions were preferentially located on the limbs and ventral thoracoabdominal wall and characterized by nodules or tumor-like masses with ulcerations and serosanguineous discharge. The cut surface showed fistulous tracts containing kunkers. The direct examination of the kunkers and microbiological culture revealed sparsely septate and branched hyaline hyphae. Histopathology revealed a marked inflammatory infiltrate of eosinophils with multifocal well-defined areas of eosinophil necrosis and collagenolysis and intralesional negatively-stained hyphal profiles; in the donkey, a pyogranulomatous inflammatory infiltrate was noted surrounding these areas. Immunohistochemistry for Pythium insidiosum revealed strong immunolabelling of the hyphae. Pythiosis occurs endemically in equidae in northeastern Brazil, with seasonal variation in the incidence. The intralesional kunkers establishes an accurate presumptive diagnosis, but confirmation should preferably be performed through histopathology associated with immunohistochemistry, culture-based or molecular methods.
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Affiliation(s)
- Erick Platiní F Souto
- Laboratory of Animal Pathology, Federal University of Campina Grande, Patos, Paraiba, Brazil.
| | - Lisanka A Maia
- Laboratory of Animal Pathology, Federal Institute of Paraiba, Sousa, Paraiba, Brazil
| | - Eldine G Miranda Neto
- Large Animal Medical Clinic, Federal University of Campina Grande, Patos, Paraíba, Brazil
| | - Glaucia D Kommers
- Pathology Department, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Felício Garino Junior
- Laboratory of Animal Pathology, Federal University of Campina Grande, Patos, Paraiba, Brazil
| | - Franklin Riet-Correa
- Post-Graduate Program in Animal Science in the Tropics, Federal University of Bahia, Salvador, Bahia, Brazil
| | - Glauco J N Galiza
- Laboratory of Animal Pathology, Federal University of Campina Grande, Patos, Paraiba, Brazil
| | - Antonio F M Dantas
- Laboratory of Animal Pathology, Federal University of Campina Grande, Patos, Paraiba, Brazil
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Yolanda H, Krajaejun T. History and Perspective of Immunotherapy for Pythiosis. Vaccines (Basel) 2021; 9:1080. [PMID: 34696188 DOI: 10.3390/vaccines9101080] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Robert MG, Cornet M, Hennebique A, Rasamoelina T, Caspar Y, Pondérand L, Bidart M, Durand H, Jacquet M, Garnaud C, Maubon D. MALDI-TOF MS in a Medical Mycology Laboratory: On Stage and Backstage. Microorganisms 2021; 9:1283. [PMID: 34204665 DOI: 10.3390/microorganisms9061283] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/31/2021] [Accepted: 06/03/2021] [Indexed: 12/12/2022] Open
Abstract
The implementation of MALDI-TOF MS in medical microbiology laboratories has revolutionized practices and significantly reduced turnaround times of identification processes. However, although bacteriology quickly benefited from the contributions of this technique, adjustments were necessary to accommodate the specific characteristics of fungi. MALDI-TOF MS is now an indispensable tool in clinical mycology laboratories, both for the identification of yeasts and filamentous fungi, and other innovative uses are gradually emerging. Based on the practical experience of our medical mycology laboratory, this review will present the current uses of MALDI-TOF MS and the adaptations we implemented, to allow their practical execution in a daily routine. We will also introduce some less mainstream applications, like those for fungemia, or even still under development, as is the case for the determination of sensitivity to antifungal agents or typing methods.
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Nonpassopon M, Jongkhajornpong P, Aroonroch R, Koovisitsopit A, Lekhanont K. Predisposing Factors, Clinical Presentations, and Outcomes of Contact Lens-Related Pythium Keratitis. Cornea 2021. [PMID: 33470674 DOI: 10.1097/ICO.0000000000002651] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Souto EPF, Maia LA, Virgínio JP, Carneiro RS, Kommers GD, Riet-Correa F, Galiza GJN, Dantas AFM. Pythiosis in cats in northeastern Brazil. J Mycol Med 2020; 30:101005. [PMID: 32522404 DOI: 10.1016/j.mycmed.2020.101005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/06/2020] [Accepted: 05/18/2020] [Indexed: 12/11/2022]
Abstract
The epidemiological, clinical and anatomopathological aspects of pythiosis in cats in northeastern Brazil are described. From January 2000 to December 2018 the Laboratory of Animal Pathology of the Federal University of Campina Grande received 1928 tissue samples of cats, three of which were diagnosed as pythiosis. Grossly, the cats showed a multinodular mass in the oral cavity associated with facial deformity (case 1), a large multinodular mass thickening the jejunum wall (case 2), and an ulcerated nodule in the skin at the base of the tail (case 3). Histologically, pyogranulomatous inflammation and necrosis, with intralesional predominantly negatively stained hyphae, were observed in all cases. Immunohistochemistry for Pythium insidiosum revealed strong immunolabelling of the hyphae. The diagnosis of pythiosis was based on the epidemiological, clinical and anatomopathological findings, and was confirmed by immunohistochemistry. Although uncommon in cats, pythiosis should be readily considered as a differential diagnosis of chronic pyogranulomatous infections of the gastrointestinal tract and skin, especially in endemic areas, where the disease is often diagnosed in other animal species.
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Affiliation(s)
- E P F Souto
- Laboratory of Animal Pathology, Federal University of Campina Grande, Patos, Paraiba, Brazil.
| | - L A Maia
- Laboratory of Animal Pathology, Federal Institute of Paraiba, Sousa, Paraiba, Brazil
| | - J P Virgínio
- Laboratory of Animal Pathology, Federal Institute of Paraiba, Sousa, Paraiba, Brazil
| | - R S Carneiro
- Laboratory of Animal Pathology, Federal University of Campina Grande, Patos, Paraiba, Brazil
| | - G D Kommers
- Pathology Department, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - F Riet-Correa
- Laboratory of Animal Pathology, Federal University of Campina Grande, Patos, Paraiba, Brazil
| | - G J N Galiza
- Laboratory of Animal Pathology, Federal University of Campina Grande, Patos, Paraiba, Brazil
| | - A F M Dantas
- Laboratory of Animal Pathology, Federal University of Campina Grande, Patos, Paraiba, Brazil
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15
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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: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Permpalung N, Worasilchai N, Chindamporn A. Human Pythiosis: Emergence of Fungal-Like Organism. Mycopathologia 2020; 185:801-12. [PMID: 31845178 DOI: 10.1007/s11046-019-00412-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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