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

Tananuvat, Napaporn; Salakthuantee, K; Vanittanakom, Nongnuch; Pongpom, Monsicha; Ausayakhun, Somsanguan

doi:10.1038/eye.2012.162

Cited by 46 publications

(46 citation statements)

References 22 publications

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“…PCR was also found to be positive for fungus in 88.9% of culture-negative cases. Tananuvat et al [12] similarly reported a sensitivity of 90.9% and a specificity of 94.7% of fungal PCR in microbial keratitis. In aggregate, these results suggest PCR techniques have high sensitivity for detection of bacterial and particularly fungal pathogens and is particularly useful for diagnosis of fungal keratitis.…”

Section: Utility Of Pcr In Evaluation Of Anterior Segment Diseasementioning

confidence: 99%

Role of Molecular Diagnostics in Ocular Microbiology

Taravati¹,

Lam²,

Gelder³

2013

Curr Ophthalmol Rep

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Although microbial culture remains the gold standard for diagnosis of many ocular infections, the technique is limited by low yield, inability to detect certain organisms, and potentially long delays to results. DNA-based molecular diagnostic techniques use detection of specific nucleic acid sequences as evidence for presence of suspected pathogens. The polymerase chain reaction (PCR) is a powerful molecular biology technique that allows for detection of fewer than 10 copies of pathogen genome. Recent technical advances in PCR have permitted quantitation of pathogen load using quantitative PCR (qPCR), and have permitted multiplexing of primer sets. Use of pan-bacterial and pan-fungal primers for ribosomal DNA sequences has allowed diagnosis of bacterial and fungal infections using molecular techniques. In this review, we highlight recent advances in the application of PCR to the diagnosis of anterior segment and posterior segment ocular infectious diseases.

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Section: Utility Of Pcr In Evaluation Of Anterior Segment Diseasementioning

confidence: 99%

Role of Molecular Diagnostics in Ocular Microbiology

Taravati¹,

Lam²,

Gelder³

2013

Curr Ophthalmol Rep

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“…In a series of 30 eyes with presumed fungal keratitis, positive fungal culture rates were 40%, whereas PCR showed positivity in 93.3% of cases. 7 In a recent report describing a series of five eyes removed for fungal endophthalmitis that were all positive for Bipolaris hawaiiensis by genotyping, three were culture negative. However, all eyes demonstrated hyphal and spore forms with fungal stains.…”

Section: Test)mentioning

confidence: 99%

“…Culture is the gold standard for demonstration of fungi in tissues, but it may yield low-positive results. 7,8 Periodic acid-Schiff (PAS) staining is another frequently used and reliable method for identification of fungi in tissues that may be superior to culture because demonstration of fungi in cultures may not be always possible. 8 In our study, we report PAS staining, fungal culture, and direct microscopy results of eyelashes pulled from patients with clinical seborrheic blepharitis or mixed seborrheic/staphylococcal blepharitis and compared with healthy controls.…”

Section: Introductionmentioning

confidence: 99%

Periodic acid–Schiff staining demonstrates fungi in chronic anterior blepharitis

Dadacı

Kılınç

Özer

et al. 2015

Eye

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Purpose To evaluate the presence of fungi in patients with chronic anterior blepharitis with periodic acid-Schiff (PAS) staining of the eyelashes in addition to the conventional methods of fungal cultures and direct microscopy. Methods Nineteen patients with chronic anterior blepharitis of seborrheic or mixed seborrheic/staphylococcal type and 11 healthy age-and sex-matched controls were included in this prospective, nonrandomized, cross-sectional study. Blepharitis was diagnosed based on clinical evidence of greasy scales between the cilia, lid margin erythema, conjunctival hyperemia, telangiectasia, thickening, or irregularity of the eyelid margins by slit-lamp biomicroscopy. Eyelash samples were obtained by epilation with a sterile forceps and evaluated with PAS staining, fungal cultures, and direct microscopy. Results We demonstrated fungal elements with PAS staining in 79% of the blepharitis group (hyphae and/or spores) and 18% of the control group. The difference was statistically significant (P = 0.002). Four patients in the blepharitis group (21%) had positive cultures for fungi. The isolated fungi were Penicillium species (2 cases), Candida species (1 case), and Trichophyton verrucosum (1 case). Direct microscopic examination revealed Demodex mites in 42.1% of the blepharitis group. No culture growth or Demodex mites were observed in the control group. Conclusions We have shown fungi with PAS staining in the majority of patients with chronic anterior blepharitis. Further controlled studies are necessary to clarify the role of fungi in the etiopathogenesis of blepharitis.

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“…PCR has been compared to the conventional diagnostic modalities of smear and culture in recent studies, displaying greater sensitivity (comparison in Table 1) and rapid results [25,26].…”

Section: Polymerase Chain Reaction (Pcr)mentioning

confidence: 99%

Fungal Keratitis: Update for 2014

Stone

Tan

2014

Curr Ophthalmol Rep

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Fungal keratitis is a challenging problem worldwide, and many obstacles remain to the effective prevention, diagnosis, and therapy of this vision-threatening condition. Recent research has highlighted progress in each of these facets of the clinical approach to keratomycosis. Increased awareness of contact lens-associated fungal keratitis has prompted regulators to pay greater attention to testing of contact lens solutions under realworld conditions. Related research has also delved into the mechanisms of fungal biofilm formation and related therapeutic targets. Advances in polymerase chain reaction methodologies promise to increase the rapidity and accuracy of diagnosis, thereby decreasing the delay in instituting appropriate therapy. Antifungal pharmacologic agents remain the first line of therapy, with the newer azole antifungal voriconazole being utilized in innovative ways, such as via intrastromal injection. Large prospective studies such as the Mycotic Ulcer Treatment Trial have helped delineate optimal treatment algorithms, and variations in surgical techniques and postoperative regimens continue to be refined. Natamycin may still be more effective than other recently utilized antifungals for the treatment of Fusarium infections, but treatment failure is still a concern. Post-keratoplasty immunosuppression may benefit from the use of topical calcineurin inhibitors such as cyclosporine and tacrolimus, given their intrinsic antifungal properties. It can be argued that the prevention, diagnosis, and treatment of fungal keratitis lag behind the state of the art for bacterial keratitis, but dramatic improvements are undoubtedly on the horizon.

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

Cited by 46 publications

References 22 publications

Role of Molecular Diagnostics in Ocular Microbiology

Role of Molecular Diagnostics in Ocular Microbiology

Periodic acid–Schiff staining demonstrates fungi in chronic anterior blepharitis

Fungal Keratitis: Update for 2014

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