RESUMEN
Background: Pythium insidiosum (P. insidiosum) is the causative agent of pythiosis, an infectious disease with a high morbidity and fatality rate. Pythiosis cases have increased dramatically during the past ten years, particularly in tropical and subtropical areas. Sadly, microbiologists and medical professionals know very little about pythiosis, and the disease is frequently challenging to identify. It is frequently misdiagnosed as a fungal infection. Methods: We report two cases of pythiosis, one was Pythium keratitis, the other was cutaneous pythiosis. The patient with corneal infection had no underlying disease, while the patient with cutaneous pythiosis had a history of liver cirrhosis, diabetes, and psoriasis. The corneal sample and subcutaneous pus were sent for metagenomic Next-Generation Sequencing (mNGS). To further diagnose the isolated strain, P. insidiosum zoospores were induced to produce by co-incubation with sterile grass leaves in sterile pond water. Their zoospores were used as an inoculum for drug susceptibility testing by disk diffusion and broth microdilution method. Results: The mNGS of two cases were reported as P. insidiosum. Zoospores were produced after incubation 48h. The zoospores were collected for drug susceptibility assay. All antifungal drugs, antibacterial drugs of ß-Lactams, vancomycin, levofloxacin, ciprofloxacin, gentamicin, trimethoprim-sulfamethoxazole, clindamycin have no inhibitory activity against P. insidiosum in vitro. Minocycline, tigecycline, linezolid, erythromycin and azithromycin have significant in vitro activity against P. insidiosum. Based on the susceptibility results, the drug was changed from itraconazole to linezolid and minocycline, along with multiple debridements and drainage for cutaneous pythiosis. The patient was discharged after 24 days of treatment. Conclusions: Early and accurate identification, combined with aggressive surgical debridement and appropriate drug therapy, can greatly improve patient managements. Conventional culture and zoospore induction remain gold standard for diagnosis; however, DNA-based method should be performed simultaneously. The drug susceptibility testing provides profound effects on proper drug selection against P. insidiosum.
Asunto(s)
Antifúngicos , Pruebas de Sensibilidad Microbiana , Pitiosis , Pythium , Pythium/aislamiento & purificación , Pythium/efectos de los fármacos , Pythium/genética , Humanos , Pitiosis/diagnóstico , Pitiosis/microbiología , Pitiosis/tratamiento farmacológico , Antifúngicos/farmacología , Antifúngicos/uso terapéutico , Masculino , Errores Diagnósticos , Enfermedades Transmisibles Emergentes/microbiología , Enfermedades Transmisibles Emergentes/diagnóstico , Enfermedades Transmisibles Emergentes/tratamiento farmacológico , Queratitis/microbiología , Queratitis/diagnóstico , Queratitis/tratamiento farmacológico , Persona de Mediana Edad , Secuenciación de Nucleótidos de Alto Rendimiento , Femenino , AncianoRESUMEN
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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Queratitis , Pitiosis , Pythium , Humanos , Animales , Queratoplastia Penetrante , Antibacterianos/uso terapéutico , Pitiosis/diagnóstico , Pitiosis/terapia , Queratitis/diagnóstico , Queratitis/tratamiento farmacológico , Queratitis/cirugía , Estudios RetrospectivosRESUMEN
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.
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Úlcera de la Córnea , Queratitis , Pitiosis , Pythium , Animales , Humanos , Pitiosis/diagnóstico , Pitiosis/terapia , Pitiosis/microbiología , Queratitis/diagnóstico , Queratitis/tratamiento farmacológico , Úlcera de la Córnea/diagnóstico , Antifúngicos/uso terapéuticoRESUMEN
Purpose: To differentiate Pythium keratitis from fungal keratitis using clinical signs, to explore usefulness of various signs as diagnostic prognosticators, and develop a clinical scoring system. Methods: A retrospective review of medical records and archived clinical photographs of patients with culture-positive Pythium keratitis and hyaline filamentous fungal keratitis was conducted at a tertiary eye institute to explore characteristics of ulcers that may aid diagnosis. Results: Full-thickness corneal stromal keratitis (P = 0.055), a dry ulcer surface (P = 0.010), tentacles (P < 0.0001), intrastromal dots (P < 0.0001), ring infiltrates (P = 0.024), reticular patterns (P < 0.0001), and peripheral furrows (P < 0.0001) were clinical signs associated with Pythium keratitis. Multiple regression analysis identified tentacles (odds ratio: 24.1, 95% confidence interval (CI): 3.8-158.1, P = 0.001) and peripheral furrows (odds ratio: 60.6, 95% CI: 5.1-712.3, P = 0.001) as independent diagnostic prognosticators for Pythium keratitis. The positive and negative likelihood ratios of a dry ulcer surface, tentacles, intrastromal dots, ring infiltrates, reticular patterns, and peripheral furrows predicting Pythium keratitis were 1.6, 13.6, 17.9, 4.3, 30.7, 15.3 and 0.4, 0.4, 0.7, 0.9, 0.6 and 0.8, respectively. The presence of two or more of these clinical signs (excluding a dry ulcer surface) had a sensitivity of 55.6% and a false positive rate of 1.4%. Conclusion: Tentacles, intrastromal dots, ring infiltrates, reticular patterns, and peripheral furrows are clinical signs to be considered for the diagnosis of Pythium keratitis and the presence of two or more signs has a very low false positive rate.
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Úlcera de la Córnea , Infecciones Fúngicas del Ojo , Queratitis , Pitiosis , Pythium , Animales , Úlcera de la Córnea/diagnóstico , Infecciones Fúngicas del Ojo/diagnóstico , Humanos , Queratitis/diagnóstico , Queratitis/microbiología , Pitiosis/diagnóstico , ÚlceraRESUMEN
PURPOSE: To assess the sensitivity of potassium hydroxide and calcofluor white (KOH+CFW) mount in the diagnosis of Pythium keratitis and concordance among microbiologists. METHODS: Three microbiologists evaluated the microscopic images of KOH + CFW mounts of confirmed cases of Pythium and fungal keratitis seen between January 2019 and February 2021. The filaments were compared using specific differentiating features. The sensitivity and specificity of KOH + CFW in diagnosing Pythium infection were evaluated along with concordance among the microbiologists. RESULTS: Sixty consecutive cases with confirmed growth of fungus or Pythium insidiosum (n = 29) were evaluated. The sensitivity of KOH + CFW in the correct identification of Pythium filaments ranged from 79.3% to 96.5% among three microbiologists. There was good interobserver (k = 0.76-0.90) and intraobserver (k = 0.70-0.97) agreements among three microbiologists. The differentiating findings (P < 0.0001) suggestive of Pythium filaments were the absence of septae in 23 (79.3%) and collapsed walls in 22 (75.9%) cases. CONCLUSION: KOH + CFW has good sensitivity and specificity in the diagnosis of Pythium keratitis with good interobserver and intraobserver concordance.
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Infecciones Fúngicas del Ojo , Queratitis , Pythium , Bencenosulfonatos , Colorantes , Córnea/microbiología , Infecciones Fúngicas del Ojo/diagnóstico , Infecciones Fúngicas del Ojo/microbiología , Hongos , Humanos , Hidróxidos , Queratitis/diagnóstico , Compuestos de PotasioRESUMEN
PURPOSE: To describe the clinical picture and outcome of a case of Pythium keratitis, presenting as peripheral ulcerative keratitis (PUK). CASE SUMMARY: A 54- year- old male presented to the clinic with a PUK in the right eye. Systemic investigations were performed to rule out associated collagen vascular disorders. Microbiological examination of corneal scrapings was performed to rule out secondary infection which revealed gram positive cocci on Gram stain. There was no growth of any organism on culture. Topical vancomycin 5% and ciprofloxacin 0.3% were started initially. On regular follow-up, there was worsening of clinical signs. Topical and oral corticosteroids were further added. Due to progressive worsening of infiltrate size and corneal perforation, therapeutic penetrating keratoplasty was performed. Pythium insidiosum (confirmed by DNA sequencing and zoospore formation) was grown from excised corneal button and the histopathology revealed filaments suggestive of Pythium species. CONCLUSION: This case describes the uncommon manifestation of Pythium insidiosum keratitis presenting as peripheral ulcerative keratitis.
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Úlcera de la Córnea , Pythium , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Purpose: The aim of this work was to study the demographic profile, clinical diagnostic features, challenges in management, treatment outcomes, and ocular morbidity of microbiological culture-proven Pythium keratitis in a tertiary eye care hospital in South India. Methods: Retrospective analysis of microbiologically proven Pythium keratitis patients was performed at a tertiary eye center from October 2017 to March 2020. Demographic details, risk factors, microbiological investigations, clinical course, and visual outcomes were analyzed. Results: Thirty patients were analyzed. The mean age was 43.1±17.2 years. Most common risk factors were history of injury in 80% and exposure to dirty water in 23.3%. Visual acuity at baseline was 20/30 to perception of light (PL). The most common clinical presentation was stromal infiltrate and hypopyon in 14 (46.6%) patients each. The microbiological confirmation was based on culture on blood agar and vesicles with zoospores formation with incubated leaf carnation method. Seven (23.3%) patients improved with topical 0.2% Linezolid and topical 1% Azithromycin, 19 (63.3%) patients underwent Therapeutic keratoplasty (TPK) and 4 were lost to follow-up. Seven (23.3%) patients had graft reinfection, and 3 (10%) developed endophthalmitis. The final visual acuity was 20/20- 20/200 in 6 (20%) patients, 20/240-20/1200 in 5 (16.6%) patients, hand movement to positive perception of light in 16 patients and no perception of light (Pthisis Bulbi) in 3 (10%) patients. Conclusion: P. insidiosum keratitis is a rapidly progressive infectious keratitis with prolonged and relapsing clinical course. It usually results in irreparable vision loss in majority of the patients. Prompt diagnosis, clinical awareness, and specific treatment options are needed for successfully managing this devastating corneal disease.
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Queratitis , Pitiosis , Pythium , Adulto , Animales , Humanos , India/epidemiología , Queratitis/diagnóstico , Queratitis/epidemiología , Persona de Mediana Edad , Pitiosis/diagnóstico , Pitiosis/epidemiología , Pitiosis/terapia , Estudios RetrospectivosRESUMEN
PURPOSE: To report clinical profile and compare management options for Pythium keratitis. METHOD: Retrospective interventional study of 46 patients diagnosed as Pythium keratitis by PCR DNA sequencing from January 2014 to July 2017. Interventions were categorised into medical management (MM) (topical azithromycin and linezolid with oral azithromycin at presentation), surgery (S) (therapeutic penetrating keratoplasty, TPK), surgical adjunct (SA) (cryotherapy±alcohol with TPK) and medical adjunct (MA) (MM after TPK). RESULTS: Primary treatment included MM (1 eye), SA (3 eyes) and S (42 eyes). Recurrence occurred in 27/43 eyes (MM+S group). Second surgery (S) was required in 11 eyes (TPK-2), with additional procedures (SA) in 10 eyes and evisceration in five eyes. 8/43 eyes received MA after TPK-1. One eye required TPK-3. Recurrence occured in all eyes that received MA (100%) and in 28 of 54 TPKs (51.8%) (TPK 1+2+3) in 42 eyes. Recurrence was noted in 1/14 (7.1%) that underwent SA. CONCLUSION: The currently available and recommended treatment for Pythium keratitis is surgical by means of a TPK and in worse cases evisceration. In our study, MM/MA measures showed no benefit with recurrence or worsening of infection requiring resurgery. Almost 50% of TPKs had a recurrence requiring resurgery. However, adjunctive procedures during TPK appear to have additional benefit with low risk of recurrence and could be included as routine care.