Comparative Study of Gram Stain, Potassium Hydroxide Smear, Culture and Nested PCR in the Diagnosis of Fungal Keratitis

Badiee, Parisa; Nejabat, Mahmood; Alborzi, Abdolvahab; Keshavarz, Fatemeh; Shakiba, Elaheh

doi:10.1159/000313988

Cited by 53 publications

(53 citation statements)

References 40 publications

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“…Direct smears were prepared for Gram's staining from Isolates and diagnosed based on morphology of the culture medium and details of microscopic examination from positive cultures on Sabouraud dextrose agar. 21 Positive isolates were sub cultured on chromogenic candida agar (Rapid Labs Ltd, Essex) which differentiates Candida species on the basis of a color change. 22 Genomic DNA extraction and purification were performed using a Genomic DNA Extraction kit (provided by Jena Bioscience GmbH/ Germany) based on the guidelines.…”

Section: Methodsmentioning

confidence: 99%

Identification of Candida spp. isolated from vaginal swab by phenotypic methods and multiplex PCR in Duhok, Iraq

Mohammed

Ali²,

Abdullah

2015

Int J Res Med Sci

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Section: Methodsmentioning

confidence: 99%

Identification of Candida spp. isolated from vaginal swab by phenotypic methods and multiplex PCR in Duhok, Iraq

Mohammed

Ali²,

Abdullah

2015

Int J Res Med Sci

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“…Aspergillus species was the most common isolate in the FK reported in India (14), south Iran (15,16) Nepal, and Bangladesh (17). However, certain Aspergillus species, mainly A. flavus (16), A. terreus (18), A. fumigatus (19), and A. niger (20), have long been regarded as important pathogens in FK. Fusarium species was found to be the most common cause of FK in south India (21), but the prevalence of the infection in other parts of the world is limited (16).…”

Section: Etiologic Agentsmentioning

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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“…There are many reports on the molecular diagnosis of systemic fungal infections (source of endogenous FK) in blood (44)(45)(46) and FK in the eye samples of patients (41,47). The sensitivity rates of molecular methods for the detection of FK were reported to be 81.6% (41), 92.6% (47), and 100% for Aspergillus keratitis by nested PCR assay (30).…”

Section: Molecular Methodsmentioning

confidence: 99%

“…Calcofluor white (CFW) highlights the fungal cell wall and increases the sensitivity of KOH to 91.4% (33), 99.0% (40), and 99.44% (6). Gram stain for detecting fungi in corneal scrapings identifies yeast but cannot visualize the hyphae of molds, with the reported sensitivity rates ranging from 42.1% (41) to 88.2% (40). Other staining can be helpful to the diagnosis of fungal hyphae in scraping samples or tissue sections.…”

Section: Direct Studymentioning

confidence: 99%

Management of Fungal Keratitis in Pediatric Patients

Badiee

Nejabat

Choopanizadeh

2017

Arch Pediatr Infect Dis

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Context: Fungal keratitis is an uncommon infection with high morbidity in pediatric patients. Trauma is the most common risk factor for infection in children. Thus, rapid diagnosis should be made by scoring clinical features and mycological examination. This review discusses the management of fungal keratitis in pediatric patients. Evidence Acquisition: In this narrative review, the most recently published data on pediatric fungal keratitis, respective prominent signs and symptoms, etiologic agents, diagnosis and treatment of this infection have been reviewed. Results: Laboratory methods such as investigation of smear by potassium hydroxide and staining and cultural and molecular methods can be helpful in the diagnosis. Treatment of this infection with improved outcome is challenging. Medical therapy (topical and systemic treatments) is the first choice of treatment, but early surgical intervention and removal of the infected tissues are critical for effective cure. Lack of response to these therapies requires corneal transplantation. Unfortunately, loss of useful vision rate was found in patients even with treatment by antifungal agents. Conclusions:The signs and symptoms of fungal keratitis are similar to those of other microbial keratitis. Use of diagnostic methods and early treatment are helpful for recovery in infected pediatric patients.

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Comparative Study of Gram Stain, Potassium Hydroxide Smear, Culture and Nested PCR in the Diagnosis of Fungal Keratitis

Cited by 53 publications

References 40 publications

Identification of Candida spp. isolated from vaginal swab by phenotypic methods and multiplex PCR in Duhok, Iraq

Identification of Candida spp. isolated from vaginal swab by phenotypic methods and multiplex PCR in Duhok, Iraq

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

Management of Fungal Keratitis in Pediatric Patients

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