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Gurnani B, Christy J, Kaur K, Moutappa F, Gubert J. Successful Management of Pythium insidiosum Keratitis Masquerading as Dematiaceous Fungal Keratitis in an Immunosuppressed Asian Male. Ocul Immunol Inflamm 2024; 32:583-586. [PMID: 36812410 DOI: 10.1080/09273948.2023.2179495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 02/24/2023]
Abstract
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.
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Affiliation(s)
- Bharat Gurnani
- Consultant Cataract, Cornea and Refractive Services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Pondicherry, India
- Sadguru Chikitsa Netralaya, Shri Sadguru Seva Sangh Trust, Chitrakoot, Madhya Pradesh, India
| | - Josephine Christy
- Consultant Cataract, Cornea and Refractive Services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Pondicherry, India
| | - Kirandeep Kaur
- Consultant Cataract, Pediatric Ophthalmology and Strabismus, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Pondicherry, India
- Sadguru Chikitsa Netralaya, Shri Sadguru Seva Sangh Trust, Chitrakoot, Madhya Pradesh, India
| | - Fredrick Moutappa
- Consultant Cataract, Pediatric Ophthalmology and Strabismus, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Pondicherry, India
| | - Joseph Gubert
- Consultant Department of Microbiology, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Pondicherry, India
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Loreto ES, Tondolo JSM, Zanette RA. Treating Pythiosis with Antibacterial Drugs Targeting Protein Synthesis: An Overview. J Fungi (Basel) 2024; 10:234. [PMID: 38667905 PMCID: PMC11051233 DOI: 10.3390/jof10040234] [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: 01/22/2024] [Revised: 03/08/2024] [Accepted: 03/18/2024] [Indexed: 04/28/2024] Open
Abstract
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.
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Affiliation(s)
- Erico S. Loreto
- Sobresp Faculty of Health Sciences, 520 Appel Street, Santa Maria 97015-030, RS, Brazil;
| | - Juliana S. M. Tondolo
- Sobresp Faculty of Health Sciences, 520 Appel Street, Santa Maria 97015-030, RS, Brazil;
| | - Régis A. Zanette
- Department of Pharmacology, Basic Health Sciences Institute, Federal University of Rio Grande do Sul, 2600 Ramiro Barcelos Street, Porto Alegre 90035-003, RS, Brazil;
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Agarwal S, Srinivasan B, Iyer G, Pandey S, Agarwal M, Dhiman R, Surya J, Anand AR. Depth, size of infiltrate, and the microbe - The trio that prognosticates the outcome of infective keratitis. Indian J Ophthalmol 2024; 72:44-50. [PMID: 38131568 PMCID: PMC10841783 DOI: 10.4103/ijo.ijo_1022_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 08/02/2023] [Accepted: 08/23/2023] [Indexed: 12/23/2023] Open
Abstract
PURPOSE To analyze the influence of infiltrate size, depth, and organism on the outcome of microbial keratitis. DESIGN Retrospective comparative study. METHODS Medical records of patients with infective keratitis, who reported from January 2015 to December 2019 to a tertiary eye care center, were analyzed. Size and depth of ulcer at presentation were the factors used to group patients, and the influence on the outcome of the organism causing it was analyzed. Grouping was as follows: group A: ulcer size <6 mm/anterior to midstromal infiltrate, group B: ulcer < 6 mm/full-thickness infiltrate, group C: ulcer >6 mm/anterior to midstromal infiltrate, group D: ulcer > 6 mm/full-thickness infiltrate. Patients with viral keratitis or unidentified organism were excluded. Response to treatment and best-corrected visual acuity (BCVA) at the final follow-up were the outcome measures. RESULTS In the study, 1117/6276 patients were included, with 60.8% patients in group A. A significant improvement in visual acuity was noted in groups A/B compared to groups C/D. Group A had the best response to medical management, irrespective of the organism. Higher risk for surgery was noted in group C compared to group B, with group A as the reference. Overall resolution with medical treatment was noted in 70% miscellaneous keratitis, 64.8% bacterial keratitis, 64.3% mixed keratitis, 62.5% acanthamoeba keratitis, 52.6% fungal keratitis, and 12.1% Pythium keratitis. Bacteria and acanthamoeba responded better to medical management than fungal keratitis, whereas Pythium had the highest risk for surgery. CONCLUSION An interplay between virulence of the organism along with depth and size of the infiltrate determines the outcome of microbial keratitis.
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Affiliation(s)
- Shweta Agarwal
- CJ Shah Cornea Services, Medical Research Foundation, Sankara Nethralaya, 18, College Road, Chennai, Tamil Nadu, India
| | - Bhaskar Srinivasan
- CJ Shah Cornea Services, Medical Research Foundation, Sankara Nethralaya, 18, College Road, Chennai, Tamil Nadu, India
| | - Geetha Iyer
- CJ Shah Cornea Services, Medical Research Foundation, Sankara Nethralaya, 18, College Road, Chennai, Tamil Nadu, India
| | - Sunita Pandey
- CJ Shah Cornea Services, Medical Research Foundation, Sankara Nethralaya, 18, College Road, Chennai, Tamil Nadu, India
| | - Manokamna Agarwal
- CJ Shah Cornea Services, Medical Research Foundation, Sankara Nethralaya, 18, College Road, Chennai, Tamil Nadu, India
| | - Richa Dhiman
- CJ Shah Cornea Services, Medical Research Foundation, Sankara Nethralaya, 18, College Road, Chennai, Tamil Nadu, India
| | - Janani Surya
- Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Appakkudal R Anand
- L and T Microbiology Research Centre, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
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Tanna V, Bagga B, Sharma S, Ahirwar LK, Kate A, Mohamed A, Joseph J. Randomized Double-Masked Placebo-Controlled Trial for the Management of Pythium Keratitis: Combination of Antibiotics Versus Monotherapy. Cornea 2023; 42:1544-1550. [PMID: 36796011 DOI: 10.1097/ico.0000000000003251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 01/07/2023] [Indexed: 02/18/2023]
Abstract
PURPOSE The aim of this study was to compare the efficacy of monotherapy (topical linezolid 0.2%) versus a combination of antibiotics (topical linezolid 0.2% and topical azithromycin 1%) for the treatment of Pythium insidiosum keratitis. METHODS Cases of P. insidiosum keratitis were prospectively randomized into group A on topical 0.2% linezolid along with topical placebo (sodium carboxymethyl cellulose [CMC] 0.5%) and group B on a combination of topical 0.2% linezolid and topical 1% azithromycin. Both groups were compared by proportion of both clinical resolution and worsening of keratitis along with the number of therapeutic penetrating keratoplasty (TPK) performed at 3 months. RESULTS We initially planned N = 66 patients but later limited to 20 (N = 10 in each group) patients owing to one interim analysis. The average size of the infiltrate in group A and B was 5.6 ± 1.5 mm and 4.8 ± 2.0 mm, respectively, with a mean Logarithm of the Minimum Angle of Resolution (logMAR) visual acuity of 2.74 ± 0.55 and 1.79 ± 1.19. At 3 months, from group A, 7 (70%) patients needed TPK and 2 patients had signs of resolution, whereas from group B, 6 (60%) patients achieved complete resolution ( P = 0.0003) and 2 were improving while only 1 needed TPK ( P = 0.02). The median duration of treatment in group A and B, with the study drugs, was 31 days (17.8-47.8) and 101.5 days (80-123.3), P value = 0.003, respectively. Final visual acuity at 3 months was 2.50 ± 0.81 and 0.75 ± 0.87, P = 0.02, respectively. CONCLUSIONS A combination of topical linezolid and topical azithromycin was found to have superior efficacy than the monotherapy with topical linezolid for the management of Pythium keratitis.
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Affiliation(s)
- Vishakha Tanna
- The Ramoji Foundation Centre of Ocular Infections, Shantilal Shanghvi Cornea Institute, L V Prasad Eye Institute, Hyderabad, India
| | - Bhupesh Bagga
- The Ramoji Foundation Centre of Ocular Infections, Shantilal Shanghvi Cornea Institute, L V Prasad Eye Institute, Hyderabad, India
| | - Savitri Sharma
- Jhaveri Microbiology Centre, L V Prasad Eye Institute, Hyderabad, India; and
| | | | - Anahita Kate
- The Ramoji Foundation Centre of Ocular Infections, Shantilal Shanghvi Cornea Institute, L V Prasad Eye Institute, Hyderabad, India
| | - Ashik Mohamed
- Ophthalmic Biophysics, L V Prasad Eye Institute, Hyderabad, India
| | - Joveeta Joseph
- Jhaveri Microbiology Centre, L V Prasad Eye Institute, Hyderabad, India; and
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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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Kate A, Thigale U, Ponnapati LP, Chaudhary S, Vishwakarma P, Sharma S, Bagga B. Outcomes of therapeutic penetrating keratoplasty in Pythium insidiosum keratitis managed with a combination of antibiotics. Indian J Ophthalmol 2023; 71:1868-1874. [PMID: 37203046 PMCID: PMC10391487 DOI: 10.4103/ijo.ijo_2862_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023] Open
Abstract
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.
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Affiliation(s)
- Anahita Kate
- Shantilal Shanghvi Cornea Institute, L V Prasad Eye Institute, Vijayawada, Andhra Pradesh, India
| | - Uma Thigale
- Shantilal Shanghvi Cornea Institute, L V Prasad Eye Institute, Vijayawada, Andhra Pradesh, India
| | | | - Simmy Chaudhary
- Shantilal Shanghvi Cornea Institute, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Pratima Vishwakarma
- Shantilal Shanghvi Cornea Institute, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Savitri Sharma
- Jhaveri Microbiology Centre, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Bhupesh Bagga
- The Ramoji Foundation for Ocular Infection, Shantilal Shanghvi Cornea Institute, L V Prasad Eye Institute, Hyderabad, Telangana, India
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D’cruz RP, Mohamed A, Das S. Clinical differentiation of keratitis due to fungus and Pythium: A photographic survey. Indian J Ophthalmol 2023; 71:510-514. [PMID: 36727350 PMCID: PMC10228981 DOI: 10.4103/ijo.ijo_913_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 09/20/2022] [Accepted: 10/27/2022] [Indexed: 02/03/2023] Open
Abstract
Purpose To evaluate the knowledge and skills of clinicians in differentiating cases of Pythium from fungal keratitis based on their clinical appearance. Methods Thirty slit-lamp photographs from culture-proven cases of Pythium and fungal keratitis were selected for conducting a prospective online-based photographic survey. The participants were asked to identify the causative organism and enlist the specific clinical features which helped in reaching the diagnosis. Both cornea specialists and clinical fellows/trainees participated in the survey. Sensitivity, specificity, and predictive values were estimated, and the factors associated with these, including the identification rates of clinical signs, were evaluated using bivariate and multivariate linear regression analyses. The identification rates between the consultants and fellows were compared. Results A total of 42 cornea specialists (28 consultants and 14 clinical fellows) participated in the survey. Clinicians were able to differentiate Pythium from fungal etiology in only 56% of cases. The differentiating ability between the consultants and fellows was statistically insignificant. Average sensitivity, specificity, and positive and negative predictive values for differentiating Pythium from fungus were 56%, 65%, 56%, and 66%, respectively. The specific clinical features enlisted by the participants to differentiate Pythium from fungus were the presence of tentacles, peripheral guttering, dot-like infiltrates, and elevated plaques. Conclusion Clinical knowledge regarding the signs and symptoms and the microbiological identification of features for Pythium are still lacking among clinicians. As the treatment protocols are distinctly different for both, it is imperative to enhance the knowledge and diagnosing ability to tackle this emerging microorganism which causes high morbidity.
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Affiliation(s)
- Rakhi P D’cruz
- Cornea and Anterior Segment Service, L V Prasad Eye Institute, Bhubaneswar, Odisha, India
| | - Ashik Mohamed
- Department Ophthalmic Biophysics, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Sujata Das
- Cornea and Anterior Segment Service, L V Prasad Eye Institute, Bhubaneswar, Odisha, India
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Aggarwal D, Mitra S, Kalra P, Bagga B, Mishra D, Takkar B. Case Report: Poor Outcome Despite Aggressive Management in Pythium insidiosum Endophthalmitis. Am J Trop Med Hyg 2023; 108:27-30. [PMID: 36509056 PMCID: PMC9833092 DOI: 10.4269/ajtmh.22-0441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 09/27/2022] [Indexed: 12/15/2022] Open
Abstract
Pythium insidiosum is a parasitic oomycete that can cause keratitis and closely resembles fungus, both clinically and morphologically. It requires a trained microbiologist for its differentiation from fungal filaments and has poor response to antifungal therapy. We present a case of primary isolation of the organism from the vitreous cavity in a case of endophthalmitis. The infection spread quickly and involved all the ocular tissues. The eye had poor visual outcome despite a sequence of rapidly completed retinal and corneal surgeries along with initiation of anti-Pythium therapy.
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Affiliation(s)
- David Aggarwal
- Anant Bajaj Retina Institute, L V Prasad Eye Institute (LVPEI), Hyderabad, India
| | | | | | | | - Dilip Mishra
- Department of Ophthalmic Pathology Laboratory, LVPEI, Hyderabad, India
| | - Brijesh Takkar
- Anant Bajaj Retina Institute, L V Prasad Eye Institute (LVPEI), Hyderabad, India
- Indian Health Outcomes, Public Health, and Economics Research Centre, LVPEI, Hyderabad, India
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The effect of topical ketamine administration on the corneal epithelium repair. Sci Rep 2022; 12:21465. [PMID: 36509846 PMCID: PMC9744879 DOI: 10.1038/s41598-022-24639-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 11/17/2022] [Indexed: 12/15/2022] Open
Abstract
The cornea is regarded as a sensitive organ to pain. Ketamine can effectively reduce postoperative neuropathic pain. We hypothesized that topical ketamine could mitigate postoperative corneal neuropathic pain. The aim of this study was to determine whether topical ketamine is safe for cornea and evaluate its effect on the repair procedure the damaged corneal tissue. Our study was performed on only the right eyes of 15 male rats. All animals underwent general anesthesia and the whole corneal epithelium was removed. All subjects were divided into two groups: group 1 (n = 8), one drop of ketamine, and group 2 (n = 7), one drop of 0.9% sodium chloride administered topically on the scraped cornea every 6 h for 7 days. The rats' s cornea was carefully monitored daily for the size of epithelial defects under a microscope and was photographed. On the eighth day, the eyes were sent for pathological examination. The eyes were examined for the amount of inflammation, neovascularization, keratinization, epithelial thickness and Descemet's membrane pathologies. The epithelial defect has healed completely on the sixth day in all rats in both groups. There was no significant difference in the speed of complete recovery between the two groups. No significant difference was observed between the two groups in terms of inflammation grade, neovascularization grade, and epithelial thickness. Our study showed that topical ketamine had no significant effect on corneal wound healing in a rat animal model and could be used safely for the management of postoperative chronic ocular pain.
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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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Yolanda H, Lohnoo T, Rujirawat T, Yingyong W, Kumsang Y, Sae-Chew P, Payattikul P, Krajaejun T. Selection of an Appropriate In Vitro Susceptibility Test for Assessing Anti- Pythium insidiosum Activity of Potassium Iodide, Triamcinolone Acetonide, Dimethyl Sulfoxide, and Ethanol. J Fungi (Basel) 2022; 8:1116. [PMID: 36354883 PMCID: PMC9692648 DOI: 10.3390/jof8111116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/12/2022] [Accepted: 10/13/2022] [Indexed: 02/12/2024] Open
Abstract
The orphan but highly virulent pathogen Pythium insidiosum causes pythiosis in humans and animals. Surgery is a primary treatment aiming to cure but trading off losing affected organs. Antimicrobial drugs show limited efficacy in treating pythiosis. Alternative drugs effective against the pathogen are needed. In-house drug susceptibility tests (i.e., broth dilution, disc diffusion, and radial growth assays) have been established, some of which adapted the standard protocols (i.e., CLSI M38-A2 and CLSI M51) designed for fungi. Hyphal plug, hyphal suspension, and zoospore are inocula commonly used in the drug susceptibility assessment for P. insidiosum. A side-by-side comparison demonstrated that each method had advantages and limitations. Minimum inhibitory and cidal concentrations of a drug varied depending on the selected method. Material availability, user experience, and organism and drug quantities determined which susceptibility assay should be used. We employed the hyphal plug and a combination of broth dilution and radial growth methods to screen and validate the anti-P. insidiosum activities of several previously reported chemicals, including potassium iodide, triamcinolone acetonide, dimethyl sulfoxide, and ethanol, in which data on their anti-P. insidiosum efficacy are limited. We tested each chemical against 29 genetically diverse isolates of P. insidiosum. These chemicals possessed direct antimicrobial effects on the growth of the pathogen in a dose- and time-dependent manner, suggesting their potential application in pythiosis treatment. Future attempts should focus on standardizing these drug susceptibility methods, such as determining susceptibility/resistant breakpoints, so healthcare workers can confidently interpret a result and select an effective drug against P. insidiosum.
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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
| | - Tassanee Lohnoo
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Thidarat Rujirawat
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Wanta Yingyong
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Yothin Kumsang
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Pattarana Sae-Chew
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Penpan Payattikul
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Theerapong Krajaejun
- Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
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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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Use of different stains for microscopic evaluation for the diagnosis of Pythium keratitis. Indian J Med Microbiol 2022; 40:521-524. [PMID: 36041948 DOI: 10.1016/j.ijmmb.2022.08.003] [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: 01/30/2022] [Revised: 07/28/2022] [Accepted: 08/02/2022] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the efficacy of various staining techniques for detection of Pythium in keratitis cases. METHODS Data of nineteen consecutive culture-positive cases of Pythium keratitis were retrospectively analysed. Corneal scrapings and corneal buttons (in the cases which underwent therapeutic penetrating keratoplasty [TPK]) were sent for microbiological and histopathological examination. The direct smears were stained with Potassium hydroxide and calcofluor white (KOH + CFW), Gram and Iodine-Potassium Iodide-Sulphuric Acid (IKI-H2SO4) stains. The corneal buttons were stained with Gomori's Methanamine Silver (GMS), Periodic Acid-Schiff (PAS) and Iodine-Potassium Iodide-Sulphuric Acid (IKI-H2SO4) stains. The positivity of various stains in detecting Pythium was studied. RESULTS Gram and KOH + CFW staining from smear was done in 16 out of 19 (84.2%) cases. KOH + CFW and Gram stains were suggestive of Pythium in 10 (62.5%) and 7 (43.8%) cases, respectively. IKI-H2SO4 staining in scraping samples was positive for Pythium in all the 4 (100%) cases in which it was performed. Half corneal buttons were positive for Pythium with IKI-H2SO4 stain as well as GMS stain in all the 18 cases that underwent TPK (100%). PAS stain showed weak to faint pink staining of Pythium filaments in 7 out of 18 cases (38.9%). CONCLUSION IKI-H2SO4 stain followed by KOH + CFW stain detects Pythium filaments most accurately in corneal scraping samples from keratitis patients, although the differences were not statistically significant. The positivity of the stains depends on astute observation by an experienced ocular microbiologist and pathologist.
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Thanathanee O, Bhoomibunchoo C, Anutarapongpan O, Suwan-apichon O, Charoensuk K, Chindamporn A. Role of Immunotherapy in Pythium insidiosum Keratitis. Am J Trop Med Hyg 2022; 107:110-112. [DOI: 10.4269/ajtmh.22-0015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 03/02/2022] [Indexed: 11/07/2022] Open
Abstract
Pythium keratitis is a potentially devastating ocular condition. Incidence of Pythium keratitis has been reported in tropical and subtropical areas. In previous reports, there were no effective or standard treatments, and combinations of medication, immunotherapy, and surgery were proposed. Pythium insidiosum antigen immunotherapy (PIAI) showed an acceptable safety profile, but its efficacy is questionable in Pythium keratitis. This retrospective review included 10 eyes from 10 patients. All cases were confirmed diagnosis of P. insidiosum keratitis by culture and/or polymerase chain reaction. Three doses of PIAI were injected at 2-week intervals in all patients. The infiltration diameter ranged from 5.2 mm to total corneal involvement, and eight cases (80%) had hypopyon. Therapeutic penetrating keratoplasty (TPK) or scleral graft were undertaken in nine cases. Enucleation was done in one case on the first visit. A second TPK was undertaken in three cases, and two globes were saved. Two cases in the globe salvage group received voriconazole via eyedrops and intracameral injection. No case received either linezolid or azithromycin. Three of nine eye globes (33.33%) were saved. PIAI did not show efficacy in the treatment of Pythium keratitis. Radical surgery including resurgery in recurrence is an approved effective treatment. The recently reported medications may offer supportive management.
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Affiliation(s)
- Onsiri Thanathanee
- Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Chavakij Bhoomibunchoo
- Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Orapin Anutarapongpan
- Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Olan Suwan-apichon
- Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Korawin Charoensuk
- Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Ariya Chindamporn
- Division of Mycology, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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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: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/06/2022] [Accepted: 02/08/2022] [Indexed: 01/27/2023] Open
Abstract
Pythiosis is a difficult-to-treat infectious disease caused by Pythium insidiosum. The condition is unfamiliar among healthcare workers. Manifestation of pythiosis is similar to other fungal infections, leading to misdiagnosis and delayed treatment. The geographical extent of pythiosis at a global scale is unclear. This study aimed to analyze the clinical information recorded in the scientific literature to comprehensively project epidemiological characteristics, clinical features, and future trends of pythiosis. From 1980 to 2021, 4203 cases of pythiosis in humans (n = 771; 18.3%) and animals (primarily horse, dog, and cow; n = 3432; 81.7%), with an average of 103 cases/year, were recruited. Pythiosis case reports significantly increased in the last decade. Pythiosis spanned 23 tropical, subtropical, and temperate countries worldwide. Some patients acquired pythiosis from a trip to an endemic country. Strikingly, 94.3% of human cases were in India and Thailand, while 79.2% of affected animals were in the U.S.A. and Brazil. Clinical features of pythiosis varied. Vascular and ocular pythiosis were only observed in humans, whereas cutaneous/subcutaneous and gastrointestinal infections were predominant in animals. Mortality depended on host species and clinical forms: for example, none in patients with ocular pythiosis, 0.7% in cows with a cutaneous lesion, 26.8% in humans with vascular disease, 86.4% in dogs with gastrointestinal pathology, and 100% in several animals with disseminated infection. In summary, this study reports up-to-date epidemiological and clinical features of pythiosis in humans and animals. It increases awareness of this life-threatening disease, as the illness or outbreak can exist in any country, not limited to the endemic areas.
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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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