Equidae pythiosis in Brazil and the world: a systematic review of the last 63 years (1960-2023).

This systematic review compiles reports of clinical pythiosis in horses, mules and donkeys from 1960 to 2023 worldwide, focusing on Brazil. We searched databases and included 71 articles detailing clinical characteristics, geographic distribution, epidemiology, diagnostic methods, therapies, and outcomes. The results showed that publications on equine pythiosis have significantly increased since 2010. Brazil reported the highest incidence, comprising 55% of cases, predominantly in the southern, northeastern, and central-western regions during summer and autumn. Cutaneous pythiosis was the most prevalent form, generally presenting as single lesions in the appendicular region, and affected females more than males. Diagnosis typically involved histopathology, used alone or with other methods. Various treatments have been employed, with surgery, often combined with chemotherapy and immunotherapy, being the most common. Notably, 80.84% of treated animals recovered, highlighting the effectiveness of these therapies in enhancing survival rates. The limitations of the study included the lack of data in published case reports, which made it difficult to collect and calculate epidemiological data. Additionally, we recognize that pythiosis in Brazil is underreported, since this disease does not have mandatory notification and several cases are not registered and/or reported in the literature. Lastly, it is hypothesized that equid pythiosis may be more widespread than currently known, and its real occurrence in Brazil remains uncertain.

Treating Pythiosis with Antibacterial Drugs Targeting Protein Synthesis: An Overview.

This review article explores the effectiveness of antibacterial drugs that inhibit protein synthesis in treating pythiosis, a difficult-to-treat infection caused by Pythium insidiosum. The article highlights the susceptibility of P. insidiosum to antibacterial drugs, such as macrolides, oxazolidinones, and tetracyclines. We examine various studies, including in vitro tests, experimental infection models, and clinical case reports. Based on our synthesis of these findings, we highlight the potential of these drugs in managing pythiosis, primarily when combined with surgical interventions. The review emphasizes the need for personalized treatment strategies and further research to establish standardized testing protocols and optimize therapeutic approaches.

Breaking-Down Barriers: Proposal of Using Cellulose Biosynthesis Inhibitors and Cellulase Enzyme as a Novel Treatment Modality for Vision Threatening Pythium Insidiosum Keratitis.

Pythium insidiosum, an Oomycete, causes severe keratitis that endangers vision. Its clinical, morphological, and microbiological characteristics are often indistinguishable from those of fungal keratitis, earning it the moniker "parafungus". Distinctive clinical hallmarks that set it apart from other forms of keratitis include radial keratoneuritis, tentacles, marginal infiltration, and a propensity for rapid limbal spread. The therapeutic approach to Pythium keratitis (PK) has long been a subject of debate, and topical and systemic antifungals and antibacterials have been tried with limited success. Approximately 80% of these eyes undergo therapeutic keratoplasty to salvage the eye. Hence, there is a need to innovate for alternative and better medical therapy to safeguard these eyes. The resistance of Pythium to standard antifungal treatments can be attributed to the absence of ergosterol in its cell wall. Cell walls of plants and algae have cellulose as an essential constituent. Cellulose imparts strength and structure and acts as the "skeleton" of the plant. Fungal and animal cell walls typically lack cellulose. The cellular architecture of Pythium shares a similarity with plant and algal cells through the incorporation of cellulose within its cell wall structure. Inhibitors targeting cellulose biosynthesis (CBI), such as Indaziflam, Isoxaben, and Quinoxyphen, serve as critical tools for elucidating the pathways of cellulose synthesis. Furthermore, the enzymatic action of cellulase is instrumental for the extraction of proteins and DNA. To circumvent this issue, we hypothesize that CBI's and cellulase enzymes can act on the Pythium cell wall and may effectively treat PK. The available literature supporting the hypothesis and proof of concept has also been discussed. We have also discussed these drugs' molecular mechanism of action on the Pythium cell wall. We also aim to propose how these drugs can be procured and used as a potential medical management option for this devastating entity.

First confirmed case of equine pythiosis in Northern Veracruz, Mexico.

A clinical case of an adult horse with invasive, ulcerative, proliferative, pyogranulomatous disease of the skin (tumor) in the shoulder region is presented. The mass had a granulomatous and crater-shaped appearance, with serosanguinous discharge and the presence of fistulas with caseous material. The tumor was removed by surgery and sent to the laboratory for diagnosis. Histopathology was performed using Grocott-Gomori methenamine silver stain. The presence of necrotic material, fibrosis, infiltrated cells, and brown-colored hyphae, characteristic of members of the genus Pythium, were observed. To identify the infecting species, conventional PCRs for the amplification of the ITS-1 was carried out. Histopathological and PCR tests confirmed infection by a Pythium insidiosum strain closely associated with previous records from the US and Central America. Our report represents the first molecularly confirmed case of equine pythiosis in Mexico.

Pins Gene Table v2.0: An Online Genome Database of 37 Pythium insidiosum Strains for Gene Content Exploration and Phylogenomic Analysis.

Unlike most pathogenic oomycetes, Pythium insidiosum infects humans and animals instead of plants. P. insidiosum has three clinically relevant genotypes/clades that cause a severe disease called pythiosis. To develop strategies for infection control, it is necessary to understand the biology and pathogenesis of this pathogen. Investigating the evolutionary mechanisms behind the host-specific adaptation is vital, and comparative genomic analysis can help with this. To facilitate genomic analysis, an online bioinformatics tool called P. insidiosum (Pins) Gene Table v2.0 was developed. This tool includes genomic data from 37 genetically diverse P. insidiosum strains and four related species. The database contains 732,686 genes, grouped into 80,061 unique clusters and further divided into core and variable categories at genus, species, and genotype levels. A high-resolution phylogenomic relationship among P. insidiosum strains and other oomycetes was projected through hierarchical clustering and core gene analyses. 3156 P. insidiosum-specific genes were shared among all genotypes and may be responsible for causing disease in humans and animals. After comparing these species-specific genes to the MvirDB database, 112 had significant matches with 66 known virulence proteins, some of which might be involved in vascular occlusion, which is a pathological feature of pythiosis. The correlation of genotypes, geographic origins, and affected hosts of P. insidiosum suggests that clade-I strains are more specific to animals, while clade-II/III strains are more specific to humans. The clade-specific genes might link to host preference. In summary, Pins Gene Table v2.0 is a comprehensive genome database accessible to users with minimal bioinformatics experience for the analysis of P. insidiosum genomes.

Potential anti-Pythium insidiosum therapeutics identified through screening of agricultural fungicides.

Pythiosis is a life-threatening infectious disease caused by the oomycete Pythium insidiosum. Clinical manifestations of pythiosis include an eye, blood vessel, skin, or gastrointestinal tract infection. Pythiosis has been increasingly reported worldwide, with an overall mortality rate of 28%. Radical surgery is required to save patients' lives due to the limited efficacy of antimicrobial drugs. Effective medical treatments are urgently needed for pythiosis. This study aims to find anti-P. insidiosum agents by screening 17 agricultural fungicides that inhibit plant-pathogenic oomycetes and validating their efficacy and safety. Cyazofamid outperformed other fungicides as it can potently inhibit genetically diverse P. insidiosum isolates while exhibiting minimal cellular toxicities. The calculated therapeutic scores determined that the concentration of cyazofamid causing significant cellular toxicities was eight times greater than the concentration of the drug effectively inhibiting P. insidiosum. Furthermore, other studies showed that cyazofamid exhibits low-to-moderate toxicities in animals. The mechanism of cyazofamid action is likely the inhibition of cytochrome b, an essential component in ATP synthesis. Molecular docking and dynamic analyses depicted a stable binding of cyazofamid to the Qi site of the P. insidiosum's cytochrome b orthologous protein. In conclusion, our search for an effective anti-P. insidiosum drug indicated that cyazofamid is a promising candidate for treating pythiosis. With its high efficacy and low toxicity, cyazofamid is a potential chemical for treating pythiosis, reducing the need for radical surgeries, and improving recovery rates. Our findings could pave the way for the development of new and effective treatments for pythiosis.IMPORTANCEPythiosis is a severe infection caused by Pythium insidiosum. The disease is prevalent in tropical/subtropical regions. This infectious condition is challenging to treat with antifungal drugs and often requires surgical removal of the infected tissue. Pythiosis can be fatal if not treated promptly. There is a need for a new treatment that effectively inhibits P. insidiosum. This study screened 17 agricultural fungicides that target plant-pathogenic oomycetes and found that cyazofamid was the most potent in inhibiting P. insidiosum. Cyazofamid showed low toxicity to mammalian cells and high affinity to the P. insidiosum's cytochrome b, which is involved in energy production. Cyazofamid could be a promising candidate for the treatment of pythiosis, as it could reduce the need for surgery and improve the survival rate of patients. This study provides valuable insights into the biology and drug susceptibility of P. insidiosum and opens new avenues for developing effective therapies for pythiosis.

Retrospective Review of Management and Overall Survival Rate of Patients With Vascular Pythiosis of the Lower Extremity: 20 Years Experience.

Pythiosis is an infectious disease in humans and animals caused by an aquatic fungus-like micro-organism, Pythium insidiosum. Vascular pythiosis is a difficult condition to treat and can lead to loss of limb in addition to being a potentially life-threatening infection. The condition is furthermore unfamiliar among healthcare workers, which often results in delayed treatment or even misdiagnosis. In this study, we report our findings, which have been gathered over a 20-year period in caring for vascular pythiosis in Maharaj Nakorn Chiang Mai Hospital, Chiang Mai, Thailand. We made a retrospective medical review of 32 patients presented with arterial occlusion who have serum anti-Pythium insidiosum antibodies. All patients underwent computed tomography angiography to confirm the level of arterial occlusion and decided on a treatment plan. Twelve out of 22 patients with infrainguinal disease, femoropopliteal or below-knee vascular occlusion, survived. The mean survival time is 6.58 years. Eight in 10 patients presented with suprainguinal disease died during the follow-up with a mean survival time of 31.6 months. The suprainguinal extension of the disease influenced the outcome, resulting in a higher mortality rate. However, patients presented with chronic limb ischemia had a much greater rate of survival compared to other clinical presentations. Extensive surgical resection combined with antifungal treatment and immunotherapy have proven to be effective in patients with vascular pythiosis in our findings.

MGI short-read genome assemblies of Pythium insidiosum (reclassified as Pythium periculosum) strains Pi057C3 and Pi050C3.

OBJECTIVES: Pythium insidiosum causes a difficult-to-treat infectious condition called pythiosis, with high morbidity and mortality. So far, genome data of at least 10 strains of P. insidiosum, primarily classified in the phylogenetic clades I and II, have been sequenced using various next-generation sequencing platforms. The MGI short-read platform was employed to obtain genome data of 2 clade-III strains of P. insidiosum (recently reclassified as Pythium periculosum) from patients in Thailand and the United States. This work is a part of our attempt to generate a comprehensive genome database from diverse pathogen strains. DATA DESCRIPTION: A 150-bp paired-end library was prepared from a gDNA sample of P. insidiosum (P. periculosum) strains Pi057C3 and Pi050C3 (also known as ATCC90586) to generate draft genome sequences using an MGISEQ-2000RS sequencer. As a result, for the strain Pi057C3, we obtained a 42.5-Mb assembled genome (164x coverage) comprising 14,134 contigs, L50 of 241, N50 of 45,748, 57.6% CG content, and 12,147 ORFs. For the strain Pi050C3, we received a 43.3-Mb draft genome (230x coverage) containing 14,511 contigs, L50 of 245, N50 of 45,208, 57.7% CG content, and 12,249 ORFs. The genome sequences have been deposited in the NCBI/DDBJ databases under the accession numbers JAKCXM000000000.1 (strain Pi057C3) and JAKCXL000000000.1 (strain Pi050C3).

PacBio long read-assembled draft genome of Pythium insidiosum strain Pi-S isolated from a Thai patient with pythiosis.

OBJECTIVES: Pythium insidiosum is the causative agent of pythiosis, a difficult-to-treat condition, in humans and animals worldwide. Biological information about this filamentous microorganism is sparse. Genomes of several P. insidiosum strains were sequenced using the Illumina short-read NGS platform, producing incomplete genome sequence data. PacBio long-read platform was employed to obtain a better-quality genome of Pythium insidiosum. The obtained genome data could promote basic research on the pathogen's biology and pathogenicity. DATA DESCRIPTION: gDNA sample was extracted from the P. insidiosum strain Pi-S for whole-genome sequencing by PacBio long-read NGS platform. Raw reads were assembled using CANU (v2.1), polished using ARROW (SMRT link version 5.0.1), aligned with the original raw PacBio reads using pbmm2 (v1.2.1), consensus sequence checked using ARROW, and gene predicted using Funannotate pipeline (v1.7.4). The genome completion was assessed using BUSCO (v4.0.2). As a result, 840 contigs (maximum length: 1.3 Mb; N50: 229.9 Kb; L50: 70) were obtained. Sequence assembly showed a genome size of 66.7 Mb (178x coverage; 57.2% G-C content) that contained 20,375 ORFs. A BUSCO-based assessment revealed 85.5% genome completion. All assembled contig sequences have been deposited in the NCBI database under the accession numbers BBXB02000001 - BBXB02000840.

Pythium insidiosum: insights into biofilm formation and antibiofilm activity of antifungal drugs.

In this study, we investigate the ability of Pythium insidiosum to form biofilms across various substrates and the antibiofilm efficacy of 8-hydroxyquinoline derivatives (8-HQs). Biofilms of P. insidiosum were cultured on polystyrene plates, contact lenses, and horsehair. We provide the first evidence of P. insidiosum's biofilm-forming capability, thus considerably expanding our understanding of its transmission and pathogenesis. Our results demonstrate that 8-HQs effectively inhibit biofilm formation and eradicate pre-existing biofilms, underscoring their potential as a novel treatment strategy for pythiosis, a disease currently lacking a gold-standard treatment. This finding has particular relevance for ocular pythiosis associated with contact lens usage and potential infection sources in animals. Our results contribute to the scientific knowledge base and directly impact innovative therapeutic interventions' development.

Generation of protoplasts provides a powerful experimental research tool for biological and pathogenicity studies of Pythium insidiosum.

INTRODUCTION: Pythiosis is a high-mortality infectious condition in humans and animals. The etiologic agent is Pythium insidiosum. Patients present with an ocular, vascular, cutaneous/subcutaneous, or gastrointestinal infection. Antifungal medication often fails to fight against P. insidiosum. The effective treatment is limited to radical surgery, resulting in organ loss. Fatal outcomes are observed in advanced cases. Pythiosis needs to be studied to discover novel methods for disease control. Genome data of P. insidiosum is publicly available. However, information on P. insidiosum biology and pathogenicity is still limited due to the lack of a cost-effective animal model and molecular tools. MATERIALS AND METHODS: We aimed to develop a high-efficiency protocol for generating P. insidiosum protoplast, and used it to set up an animal model, in vitro drug susceptibility assay, and DNA transformation for this pathogen. RESULTS: P. insidiosum protoplast was successfully generated to establish a feasible pythiosis model in embryonic chicken eggs and an efficient in vitro drug susceptibility assay. DNA transformation is a critical method for gene manipulation necessary for functional genetic studies in pathogens. Attempts to establish a DNA transformation method for P. insidiosum using protoplast were partly successful. Significant work needs to be done for genetically engineering a more robust selection marker to generate stable transformants at increased efficiency. CONCLUSION: This study is the first to report an efficient P. insidiosum protoplast production for clinical and research applications. Such advances are crucial to speeding up the pathogen's biology and pathogenicity exploration.

The Use of Mefenoxam to Treat Cutaneous and Gastrointestinal Pythiosis in Dogs: A Retrospective Study.

Pythium insidiosum, an aquatic oomycete with pathogenic potential in mammals, causes gastrointestinal and cutaneous disease in dogs. Mefenoxam, an agricultural anti-oomycotic compound, has a demonstrated the ability to inhibit P. insidiosum growth in vitro and has been associated with efficacy in treating gastrointestinal pythiosis in several case reports. Electronic medical records of dogs seen at University of Florida Small Animal Hospital and treated with mefenoxam between 2013 and 2020 were searched. Dogs were included in this study upon previous definitive diagnosis with either organism identification using culture, PCR, or antibody ELISA, or a combination of these tests with or without supportive histopathological analysis. Since 2013, mefenoxam had been administered to 25 dogs with cutaneous pythiosis and 16 dogs with gastrointestinal pythiosis. In both gastrointestinal and cutaneous pythiosis groups, the administration of mefenoxam was associated with a survivability rate of approximately 51%. There was a statistically significant difference in the time to death between cutaneous (245 days (52-530)) and gastrointestinal (90 days (21-203)) groups; dogs infected with cutaneous pythiosis survived significantly longer after being diagnosed with the disease (p = 0.035). The dogs in this study experienced increased survival rates and time to death, in the absence of side effects due to mefenoxam, compared with previously published literature. The results of this retrospective study, with some limitations, are promising and should prompt further investigation into the use of mefenoxam in the treatment of both gastrointestinal and cutaneous pythiosis.

Cutaneous Pythiosis in 2 Dogs, Italy.

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.

Predicting Prognosis Based on Regional Prevalence, Ulcer Morphology and Treatment Strategy in Vision-Threatening Pythium insidiosum Keratitis.

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.

Outcomes of therapeutic penetrating keratoplasty in Pythium insidiosum keratitis managed with a combination of antibiotics.

Purpose: To describe the clinical outcomes of therapeutic penetrating keratoplasty (TPK) in patients with Pythium insidiosum keratitis following treatment with anti-pythium therapy (APT) consisting of linezolid and azithromycin. Methods: A retrospective review of medical records from May 2016 to December 2019 of patients with P. insidiosum keratitis was carried out. Patients who were treated with APT for a minimum of 2 weeks and then subsequently underwent TPK were included in the study. Data on demographic characteristics, clinical features, microbiology characteristics, and intraoperative details, postoperative outcomes were documented. Results: A total of 238 cases of Pythium keratitis were seen during the study period and 50 cases that satisfied the inclusion criteria were included. The median of the geometric mean of the infiltrate was 5.6 mm (IQR 4.0-7.2 mm). The patients received topical APT for a median of 35 days (IQR 25-56) prior to surgery. The most common indication of TPK was worsening keratitis (41/50, 82%). No recurrence of infection was observed. An anatomically stable globe was noted in 49/50 eyes (98%). The median graft survival rate was 2.4 months. A clear graft was present in 10 eyes (20%) with a final median visual acuity of 20/125 after a median follow-up period of 18.4 months (IQR 11-26 months). Graft size of less than 10 mm [OR: 5.824 (CI:1.292-41.6), P = 0.02] was found to be significantly associated with a clear graft. Conclusion: Performing TPK following the administration of APT has good anatomical outcomes. A smaller graft of <10 mm was associated with a higher chance of graft survival.

Successful Management of Pythium insidiosum Keratitis Masquerading as Dematiaceous Fungal Keratitis in an Immunosuppressed Asian Male.

PURPOSE: To describe the first case of Pythium insidiosum keratitis masquerading as dematiaceous fungal keratitis in a seropositive male. CASE SUMMARY: A 44-year-old seropositive male previously treated for acute retinal necrosis presented with pain and defective vision in the right eye following a mud injury 5 days back. Presenting visual acuity was hand movements close to the face. Ocular examination revealed a 7 × 7 mm dense, greyish-white mid stromal infiltrate with pigmentation and few tentacles. The clinical diagnosis suggested fungal keratitis. Corneal scraping on 10% KOH and Gram stain revealed slender, aseptate hyaline hyphae. Before culture results, the patient was treated with topical 5% natamycin and 1% voriconazole, but the infiltrate progressed. Culture on 5% sheep blood agar revealed white fluffy, submerged, shiny, and appressed colonies, and Pythium insidiosum was confirmed by zoospore formation. The patient was further managed with topical linezolid 0.2% hourly, azithromycin 1% hourly, and adjuvant drugs. CONCLUSION: This is an uncommon presentation of Pythium keratitis masquerading as dematiaceous fungal keratitis in an immunocompromised male.

Comparative Genomic Analysis Reveals Gene Content Diversity, Phylogenomic Contour, Putative Virulence Determinants, and Potential Diagnostic Markers within Pythium insidiosum Traits.

Pythium insidiosum has successfully evolved into a human/animal filamentous pathogen, causing pythiosis, a life-threatening disease, worldwide. The specific rDNA-based genotype of P. insidiosum (clade I, II, or III) is associated with the different hosts and disease prevalence. Genome evolution of P. insidiosum can be driven by point mutations, pass vertically to the offspring, and diverge into distinct lineages, leading to different virulence, including the ability to be unrecognized by the host. We conducted comprehensive genomic comparisons of 10 P. insidiosum strains and 5 related Pythium species using our online "Gene Table" software to investigate the pathogen's evolutionary history and pathogenicity. In total, 245,378 genes were found in all 15 genomes and grouped into 45,801 homologous gene clusters. Gene contents among P. insidiosum strains varied by as much as 23%. Our results showed a strong agreement between the phylogenetic analysis of 166 core genes (88,017 bp) identified across all genomes and the hierarchical clustering analysis of gene presence/absence profiles, suggesting divergence of P. insidiosum into two groups, clade I/II and clade III strains, and the subsequent segregation of clade I and clade II. A stringent gene content comparison using the Pythium Gene Table provided 3263 core genes exclusively presented in all P. insidiosum strains but no other Pythium species, which could involve host-specific pathogenesis and serve as biomarkers for diagnostic purposes. More studies focusing on characterizing the biological function of the core genes (including the just-identified putative virulence genes encoding hemagglutinin/adhesin and reticulocyte-binding protein) are needed to explore the biology and pathogenicity of this pathogen.

Oomicidal activity of polypyrrole nanoparticles against Pythium insidiosum.

This study evaluated in-vitro action of a new molecule, the polypyrrole nanoparticles (Ppy-NP), against Pythium insidiosum isolates using M38-A2/CLSI; the minimal inhibitory (MIC) and minimal oomicidal (MOC) concentrations were also determined. Additionally, changes in the hyphae wall of P. insidiosum CBS 575.85 treated with Ppy-NP were evaluated by scanning electron microscopy (SEM). The MIC100 and MOC for all isolates ranged from 8 to 32 µg mL-1, and the MIC90 and MIC50 were 16 µg mL-1. The SEM showed structural damage to the hyphae of P. insidisoum treated with Ppy-NP, as hyphae surfaces with less turgidity were found, thereby showing scaling and ruptures compared to the control (untreated hyphae). Our findings highlighted the anti-P. insidiosum properties of Ppy-NP proved to be a promising candidate for research using pythiosis experimental models.

Pythium insidiosum keratitis: Review of literature of 5 years' clinical experience at a tertiary eye care center.

BACKGROUND: Pythium insidiosum is an important cause of infectious keratitis from tropical and sub-tropical countries. Due to its closely mimicking clinical and microbiological features with fungus, it remained unidentified and managed as fungal keratitis for a long time. Previously all patients had poor outcomes with antifungal therapy and needed surgical treatment with higher rates of recurrences of infection leading to loss of an eye. Thus, a novel approach was required to treat it and, in this article, we would like to elaborate on the drastic change which these 5 years have brought in the management of this condition. METHODS: In view of making a consolidated article comprising all the required information and also our clinical experience in the management of Pythium keratitis, we extensively reviewed several articles available on it over PubMed and Google scholars. Relevant literature describing details about Pythium, its clinical correlation, and recent advances from 52 articles including 12 articles from our group were finally included. RESULTS: Our group identified and highlighted the unique clinical and microbiological features of Pythium insidiosum, performed several in-vitro, in-vivo studies along with clinical trials, and proposed the strategic way of its diagnosis and treatment. The use of antifungals was replaced with antibacterial medications and this resulted in better medical and surgical outcomes. CONCLUSION: The diagnosis and management of Pythium insidiosum is constantly evolving with several recent works pointing out the possible changes in the practice patterns for the management of this challenging form of keratitis.