Polymerase Chain Reaction-Guided Diagnosis of Mycotic Keratitis: A Prospective Evaluation of Its Efficacy and Limitations

Vengayil, Sujith; Panda, Anita; Satpathy, Gita; Nayak, Niranjan; Ghose, Supriyo; Patanaik, Dipika; Khokhar, Sudarshan

doi:10.1167/iovs.07-1283

Cited by 69 publications

(67 citation statements)

References 21 publications

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“…The results are highly specific but have suboptimal sensitivity varying in different studies; 68.4% (21), 37.5% (20) and 25% (30). Although culture is considered as the gold standard for FK diagnosis, the major limitations are the length of time consumed for confirming the culture growth because the fungi often have a slow growth, and a high chance of culture media contamination.…”

Section: Diagnosis Of Fungal Keratitismentioning

confidence: 99%

Mycotic Keratitis, a State-of-the-art Review

Badiee

2013

Jundishapur J Microbiol

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Microbial corneal diseases are a serious ocular infection and the major cause of ocular morbidity and blindness in the world. The outcomes of fungal keratitis are unfavorable due to the protracted course of the condition and the diversity of respective clinical presentations. Trauma, contact lens wear, foreign material, and prior corneal surgery, may make the most background for permitting invasion by exogenous fungi by injecting the fungal conidia directly in the corneal stroma. Other risk factors consist of blocked naso-lacrimal duct, and ocular surface disease. More than 105 species of fungi, such as Aspergillus spp., Fusarium spp., Candida spp., Rhizopus, Mucor, and other fungi have been identified as the etiological agents of fungal keratitis. The first step of diagnosis begins with clinical suspicion, followed by corneal scrapings or biopsy for direct smear and culture confirming the etiological agent. Slit lamp biomicroscope is used for careful examination of the infected eye and pictorial documents like the ulcer size, site, depth, extent of infiltration, abscess formation, and any perforation are evaluated. Direct smears are prepared by potassium hydroxide wet mount, or Gram's staining. To identify the isolates, a lactophenol cotton blue wet mount is prepared, and diagnosis is based on morphology of the culture media and details of microscopic examination. The results are highly specific but have suboptimal sensitivity varying in different studies. Molecular assays are valuable for the diagnosis of fungal keratitis in patients. Various advantages and limitations are reported for such methods. Overall, PCR is a sensitive and promising tool for the diagnosis of fungal keratitis but the expertise required and the lack of sophisticated facilities renders it inferior to the smear techniques in routine laboratory procedures and is not recommended accordingly. Rapid diagnosis and proper treatment are essential for fungal keratitis, and many patients require several months of therapy until the infiltrate is resolved and epithelial stroma are healed. Patients not responsive to antifungal therapy usually require corneal transplantation. Keywords: Corneal Ulcer; Keratitis; Eye InfectionsImplication for health policy/ practice/ research/ medical education: Rapid diagnosis andproper treatment are essential for fungal keratitis, and many patients require several months of therapy until the infiltrate is resolved and epithelial stroma is healed. Patients not responsive to antifungal therapy usually require corneal transplantation.

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Section: Diagnosis Of Fungal Keratitismentioning

confidence: 99%

Mycotic Keratitis, a State-of-the-art Review

Badiee

2013

Jundishapur J Microbiol

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“…This is consistent with many other PCR-based detection techniques for fungal infections, 3,10,16,17 although lower values of 65-89% also were reported. 1,8,9,18,22 The diagnostic sensitivity of the PCR method was 96%. This value falls within the range of sensitivities (70-100%) reported for similar assays.…”

Section: Discussionmentioning

confidence: 98%

“…This value falls within the range of sensitivities (70-100%) reported for similar assays. 1,[8][9][10][16][17][18]22 Diagnostic sensitivity of PCR (96%) was significantly greater than that of the culture method (54%). In only one instance did culture detect G. destructans when PCR did not.…”

Section: Discussionmentioning

confidence: 99%

Rapid Polymerase Chain Reaction Diagnosis of White-Nose Syndrome in Bats

Lorch

Gargas²,

Meteyer

et al. 2010

J VET Diagn Invest

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Abstract. A newly developed polymerase chain reaction (PCR)-based method to rapidly and specifically detect Geomyces destructans on the wings of infected bats from small quantities (1-2 mg) of tissue is described in the current study (methods for culturing and isolating G. destructans from bat skin are also described). The lower limits of detection for PCR were 5 fg of purified fungal DNA or 100 conidia per 2 mg of wing tissue. By using histology as the standard, the PCR had a diagnostic specificity of 100% and a diagnostic sensitivity of 96%, whereas the diagnostic sensitivity of culture techniques was only 54%. The accuracy and fast turnaround time of PCR provides field biologists with valuable information on infection status more rapidly than traditional methods, and the small amount of tissue required for the test would allow diagnosis of white-nose syndrome in live animals.

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“…Los mé-todos moleculares como la Reacción en Cadena de la Polimerasa (PCR), para la detección de ácidos nucleicos resulta práctica dada la rapidez con que se obtienen los resultados (29), pero este método diagnóstico no siempre esta disponible en todas las instituciones de salud. Algunos autores han establecido la sensibilidad de las pruebas moleculares entre un 70-97% con una especificidad mayor al 98% (30).…”

Section: Carlos Pérez Díaz Patricia Barrios Castañeda José David MIunclassified

Colección corneal intraestromal y queratitis por Fusarium Spp: presentación de dos casos y revisión de la literatura

Díaz

Castañeda

Echavarría³

et al. 2013

Rev. Med.

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ResumenLas infecciones oculares por hongos filamentosos han aumentado su incidencia con el pasar de los años. Los traumas corneales, la terapia inmunosupresora y el uso de lentes de contacto han hecho que éstas aumenten su incidencia, pero existe un pequeño porcentaje de paciente que sin ningún factor de riesgo presentan infecciones por estos mohos. En este artículo reportamos dos casos de infección ocular por Fusarium spp. en dos pacientes de 21 y 30 años de edad respectivamente, inmunocompetentes, pertenecientes a las Fuerzas Militares y sin factores de riesgo asociados.Palabras Clave: Queratitis fúngica, moho, Fusarium spp. COLLECTION INTRASTROMAL CORNEAL AND KERATITIS BY FUSARIUM SPP: REPORT OF TWO CASES AND REVIEW OF THE LITERATURE AbstractThe filamentous fungal eye infections have been increasing in incidence in the last years. Corneal trauma, immunosuppressive therapy and use of contact lenses have increased their incidence, nonetheless a small percentage of patients with no risk factors still present with these mold infections. In this article we report a case of ocular infection by Fusarium spp. in two patients, a 21-year-old and a 30-year-old males. They work with the Military Forces, and were immunocompetent with no risk factors associated to the problem.

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Polymerase Chain Reaction-Guided Diagnosis of Mycotic Keratitis: A Prospective Evaluation of Its Efficacy and Limitations

Abstract: PCR not only proved an effective rapid method for the diagnosis of fungal keratitis, but was also more sensitive in our hands than KOH wetmount and Gram's smear. Barring the potential limitations, PCR remains a promising tool for faster diagnoses of fungal keratitis.

Cited by 69 publications

References 21 publications

Mycotic Keratitis, a State-of-the-art Review

Mycotic Keratitis, a State-of-the-art Review

Rapid Polymerase Chain Reaction Diagnosis of White-Nose Syndrome in Bats

Colección corneal intraestromal y queratitis por Fusarium Spp: presentación de dos casos y revisión de la literatura

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