Non-cultural diagnostic methods of fungal keratitis

Belskaia, K.I.; Obrubov, A.S.

doi:10.21689/2311-7729-2018-18-1-37-41

Cited by 3 publications

(5 citation statements)

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“…This method is fast and easy to perform. Different ways of specimen staining are usually used: Gram or Giemsa staining, fixation with potassium hydroxide solution, staining with lactophenol cotton blue, Shiff reagent, Gomori methenamine silver staining [ 85 , 87 ]. Corneal scrapes, bioptate, or a corneal fragment taken during penetrated keratoplasty may serve as a biomaterial.…”

Section: Diagnosismentioning

confidence: 99%

“…Staining in direct microscopy allows for visualization of hyphae and their relative position, evaluation of mycelium type [ 87 ]. Sensitivity of the method varies depending on the staining technique and reaches on average 90% [ 85 , 88 ].…”

Section: Diagnosismentioning

confidence: 99%

“…The successful application of this method depends on the depth of corneal damage, amount and quality of the collected material, and researcher experience. The probability of non-uniform staining of the preparation and artifact detection is also high; besides, this method is not always successful in relation to the Candida genus [ 85 , 87 ].…”

Section: Diagnosismentioning

confidence: 99%

“…A tear from an affected and healthy eye is analyzed for its protein composition since in fungal lesions, the content of proteins changes in a specific way [ 96 ]. The investigations of MALDI-TOF MS sensitivity show contradictive results varying from 51% [ 21 ] to 97% [ 87 ]. Not readily available, expensive, requiring constant replenishment of the data bank with microorganism proteomes are the disadvantages that prevent this method from becoming the main technique in the diagnosis of fungal keratitis [ 101 ].…”

Section: Diagnosismentioning

confidence: 99%

“…Despite a wide spectrum of the known diagnostic technologies, none of the methods meet all the requirements of clinical practice (see the Table ), therefore the development of new approaches to the detection of fungal keratitis is going on [ 87 ]. In the in vivo investigations on the murine model of Aspergillus keratitis, a non-invasive probe consisting of fluorophore-labeled antifungal preparation has been tested.…”

Section: Diagnosismentioning

confidence: 99%

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Modern Technologies in Diagnosis of Fungal Keratitis (Review)

Sitnova¹,

Svetozarskiy²

2023

Sovrem Tehnol Med

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Traumas and infectious diseases of the eye play a leading role in the development of corneal blindness responsible for 1.5–2 million cases of vision loss per year. To date, the issue of reducing the incidence of fungal keratitis is acute and needs to be solved worldwide. Trauma as a risk factor for corneal fungal disease is thought to be prevalent in developing countries due to agricultural involvement, while in developed countries the onset of the disease is predisposed by medical advances such as contact vision correction and modern ophthalmic surgery. Thorough analysis of the pathogenesis gives the possibility to describe the action of fungal enzymes, biofilm formation, and the resistance mechanism, which on the one hand explains the aggressive course of the disease and difficulties in its diagnosis, and on the other hand, it encourages searching for new methods of diagnosis and treatment. The non-specific clinical picture of fungal keratitis, the variety and availability of antibiotics nowadays become an obstacle for rapid detection of this pathology. Low public awareness and late visit to an ophthalmologist are also a barrier to successful combating the increasing incidence of fungal keratitis. Belated diagnosis, increasing resistance of fungi to antibiotics, and lack of registered antifungal ophthalmic drugs justify poor treatment efficacy resulting in decreased visual acuity or vision loss . Existing diagnostic methods need systematization and detailed comparison, identifying the advantages and disadvantages of each. This review considers causative agents and their influence on pathogenesis of the disease, describes difficulties of fungal keratitis diagnosis and possible ways of overcoming these problems using new developments, and also outlines further prospects of research in this direction.

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Section: Diagnosismentioning

confidence: 99%

Section: Diagnosismentioning

confidence: 99%

Section: Diagnosismentioning

confidence: 99%

Section: Diagnosismentioning

confidence: 99%

Section: Diagnosismentioning

confidence: 99%

See 3 more Smart Citations

Modern Technologies in Diagnosis of Fungal Keratitis (Review)

Sitnova¹,

Svetozarskiy²

2023

Sovrem Tehnol Med

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The Effectiveness of PCR in Diagnosis of Fungal Keratitis

et al. 2020

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Fungi implicated in mycotic keratitis include different species. Conventional methods for the diagnosis of fungal keratitis include staining of corneal scarpings, culture medium (Sabouraud agar) for isolating fungi.Purpose. To evaluate the effectiveness of polymerase chain reaction (PCR) for the detection of fungal etiology in comparison with the conventional diagnostic methods in cases with suspected fungal corneal ulcer.Patients and methods. Seven patients with severe corneal ulcers with more than 3 weeks duration. Corneal scarpings and corneal buttons from seven patients who had undergone therapeutic keratoplasty were used for microbiological and PCR analysis. PCR diagnostic kits for the differential detection of Candida albicans DNA and total fungi DNA (DNA Fungi), which allows to identify most pathogenic fungi without determining their species were used. Microbiological methods: microscopy of gramstained smears, culture techniques, including selective for fungi agar Saburo with chloramphenicol.Results. PCR: Fragments of all corneas removed from keratoplasty (6 patients) revealed fungal-common DNA (Fungi DNA) and did not detect Candida albicans DNA, which correlated with sowing results on Saburo medium (mold fungi found in 5 of 6 corneas). Fungi DNA was also detected in the corneal scraps taken prior to surgery; however, growth of fungi during sowing on various nutrient media was not found.Conclusion. Corneal fungal ulcers are a serious disease, often leading to visual disability. The rapid determination of etiology and the correct choice of therapy determines the outcomes of the disease. The advantage of PCR over the culture method: the speed of obtaining results (4 hours instead of 3–7 days); high sensitivity, which allows detecting fungi not only in the tissue of the removed cornea, but also in scrapes from the cornea ulcer of patients who previously received antifungal therapy. The presence of commercial kits for differential detection of fungal-common DNA and DNA of Candida albicans extends the possibilities of PCR in the screening diagnosis of fungal keratitis and the selection of drugs before determining the type of pathogen.

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Fungal corneal ulcer complicated by endophthalmitis: clinical and laboratory diagnostics, treatment tactics

Kovaleva

Krichevskaya

Макаров

et al. 2022

Rossijskij oftalʹmologičeskij žurnal

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Purpose: to study the clinical signs and effectiveness of laboratory diagnostics of fungal corneal ulcer complicated by endophthalmitis aimed at treatment tactics optimization.Materials and methods. 15 patients aged 20–55 with severe monocular fungal ulcer complicated by endophthalmitis were examined by microscopy and culture of corneal scraping on Sabouraud Agar; microscopy and culture of intraocular fluid and corneal fragments, obtained during the surgical treatment. Corneal scrapings from the corneal ulcer and corneal fragments removed during keratoplasty were tested in polymerase chain reaction (PCR) for the presence of deoxyribonucleic acid (DNA) of Candida albicans and total Fungi DNA.Results. Before treatment start, 2.5 hours after the biomaterial was taken, PCR revealed Fungi DNA in all 15 cases. Symptoms of the severe fungal corneal ulcer complicated by endophthalmitis and caused by Aspergillus spp have been identified and described. Conservative therapy and total penetrating keratoplasty (PKP) helped retain the eye in 13 out of 15 patients (86.7 %) and partially restore the visual functions.Conclusion. Rapid laboratory diagnosis of ophthalmomycosis using PCR offers an advantage over the culturing technique: the results are ready within 2.5 hours instead of 10-14 days (culture method); it is highly sensitive and allows identifying the fungi not only in the tissue of the removed cornea, but also in the сorneal scrapings. The effective treatment tactics of fungal corneal ulcer complicated by endophthalmitis combining PKP with pre-operative and long-term postoperative antifungal therapy was proposed.

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Non-cultural diagnostic methods of fungal keratitis

Cited by 3 publications

References 0 publications

Modern Technologies in Diagnosis of Fungal Keratitis (Review)

Modern Technologies in Diagnosis of Fungal Keratitis (Review)

The Effectiveness of PCR in Diagnosis of Fungal Keratitis

Fungal corneal ulcer complicated by endophthalmitis: clinical and laboratory diagnostics, treatment tactics

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