Prospective Comparison of Microbial Culture and Polymerase Chain Reaction in the Diagnosis of Corneal Ulcer

Kim, Elma; Chidambaram, Jaya D.; Srinivasan, Muthiah; Lalitha, Prajna; Wee, Daniel; Lietman, Thomas M.; Whitcher, John P.; Gelder, Russell N. Van

doi:10.1016/j.ajo.2008.06.009

Cited by 85 publications

(93 citation statements)

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“…21 These unusual fungi identified by PCR might be uncultured by routine media, as has been reported from previous studies. 20,22,23 A. alternata has been reported as a corneal pathogen by PCR. 24 In this series, A. alternata was identified in one case by PCR analysis whereas Fusarium species was grown on a routine culture.…”

Section: Discussionmentioning

confidence: 99%

“…Botryosphaeria was reported as a new emerging pathogen causing ocular disease. 20 Phanerochaete, which was teleomorph or the sexual state of Sporotrichum, was considered as a rare and emerging agent causing hyalohyphomycosis in humans. 21 These unusual fungi identified by PCR might be uncultured by routine media, as has been reported from previous studies.…”

Section: Discussionmentioning

confidence: 99%

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Prospective comparison between conventional microbial work-up vs PCR in the diagnosis of fungal keratitis

Tananuvat

Salakthuantee

Vanittanakom

et al. 2012

Eye

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Purpose The PCR was compared with routine microbial studies for the detection of fungal pathogens in clinically suspected fungal keratitis. Methods A prospective nonrandomized study was undertaken at a tertiary eye care centre to evaluate 30 eyes of 30 patients with presumed fungal keratitis, both fresh and treated. Corneal scrapings were performed on each patient. The specimens were analysed by a semi-nested PCR assay using fungalspecific primers. PCR products were cloned and sequenced for identification, and compared with a conventional microbial work-up (smear and culture). Results Of the 30 samples, the PCR showed positivity in 93.3%, culture in 40%, and potassium hydroxide in 20%. Of the 28 PCR-positive cases, 12 were culture-positive and 16 were culture-negative. Two samples were both PCR and culture test negative. Culture-negative samples were PCR-positive in 16 of 18 (88.9%) cases. The PCR did not yield any false-negative findings in a culturepositive specimen. Both common and uncommon aetiologic fungi have been identified by DNA sequencing analysis. Conclusion The PCR was able to detect fungal DNA in a high proportion of culturenegative cases. Technical considerations of the PCR process include extraction of artifacts and amplification of non-pathogenic DNA. Nonetheless, our findings suggest that the PCR can be a useful adjunct to smear and culture in the rapid diagnosis of fungal keratitis, particularly in cases of failed detection from routine procedures.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Prospective comparison between conventional microbial work-up vs PCR in the diagnosis of fungal keratitis

Tananuvat

Salakthuantee

Vanittanakom

et al. 2012

Eye

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“…False positive results may also occur during the DNA sequencing due to the high sensitivity of this method, although attention to reducing falsepositive results from contaminating DNA is warranted (44). Contamination of samples may occur in each stage of sampling or in reagents during processing of positive control specimens and amplification of nonpathogenic organisms.…”

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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“…Otros autores han encontrado que Fusarium spp. es el principal patógeno encontrado en las muestras oculares (24,25,26).…”

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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Prospective Comparison of Microbial Culture and Polymerase Chain Reaction in the Diagnosis of Corneal Ulcer

Cited by 85 publications

References 58 publications

Prospective comparison between conventional microbial work-up vs PCR in the diagnosis of fungal keratitis

Prospective comparison between conventional microbial work-up vs PCR in the diagnosis of fungal keratitis

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

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

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