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Neuroinfectious Diseases
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
Jeremy D. Young, Jesica A. Herrick, Scott Borgetti
Cryptococci are often easily seen on Gram stain of spinal fluid; however, special stains are more specific for the organism. The polysaccharide capsule can be observed using India ink, methenamine silver, or mucicarmine stains. India ink staining is less often available in laboratories, but mucicarmine stains are almost always available, because they are also used to diagnose adenocarcinomas. More than 80% of patients with AIDS and cryptococcal meningoencephalitis have a positive India ink examination of the CSF.3 Calcofluor white is a sensitive fluorescent stain that can be used to detect yeast by microscopy.
Trichosporon
Published in Rossana de Aguiar Cordeiro, Pocket Guide to Mycological Diagnosis, 2019
João Nobrega de Almeida Júnior
Biopsies must have a carefully microscopic examination on 20% potassium hydroxide. Fluorescent brighteners like calcofluor white help to better visualize fungal elements among tissue cells and components. For fungal cultures, the biopsies should be minced and in several pieces and inoculated on different media, including selective and non-selective agar, selective broth (e.g., brain heart infusion with antibiotics such as gentamicin and chloramphenicol), and incubated at 30°C for 4 weeks according to the standard protocols (Jorgensen et al., 2015). For inoculation of solid media, previous-scratch the agar and place the tissue into the scratch for better recovery of the fungi.
Fungal Keratitis Due to Fusarium
Published in Mahendra Rai, Marcelo Luís Occhiutto, Mycotic Keratitis, 2019
Alexandro Bonifaz, Lorena Gordillo-García, Scarlett Fest-Parra, Andrés Tirado-Sánchez, Karla García-Carmona
With the sample, smears are made that can be stained with various techniques such as Giemsa, PAS, acridine orange, Grocott and Papanicolaou; it is also suggested to place direct examination with 10% potassium hydroxide (KOH). Thin hyphae, septa and short, sometimes irregular hyphae can be observed under the microscope. Direct examinations with calcofluor white are also very useful; however, a direct fluorescence microscope is required. In general, direct microscopy and staining are rapid tests, but with low sensitivity (60-70%) and specificity (40-66%), sometimes resulting in false negatives, so they must be repeated; however, they are the most used tests in laboratories of underdeveloped countries, where this disease is more common (Kanungo et al. 1991, Thomas et al. 1991, Sharma et al. 1998, Sharma et al. 2002, Bonifaz et al. 2015, van Diepeningen et al. 2015) (Figs. 2.1D, E).
Strategies to improve the diagnosis and clinical treatment of dermatophyte infections
Published in Expert Review of Anti-infective Therapy, 2023
Furthermore, nail clippers, curettes, and scalpels are preferred for sample collection from patients with onychomycosis. A 10–20% KOH solution is dripped onto the materials placed on the slide and left for 15–20 min to dissolve the keratin structures [6]. Subsequently, microscopic examination is performed to detect fungal spores and hyphae. Although an experienced dermatologist finds it very easy to distinguish hyphae and spores during microscopic examination, this method is not applied in many dermatology clinics as some dermatologists still do not use microscopy. The high cost of microscopes is one of the factors that limit the use of microscopy in routine practice. To eliminate this issue, portable microscopes that can be mounted on smartphones have been developed in recent years [7], and fluorescent dyes such as Parker blue ink, chlorazol black and calcofluor white have been developed to distinguish artifacts and identify fungal elements more easily (Figures 3A and 3B) [8]. Although calcofluor white requires a fluorescence microscope, smartphone-based fluorescence microscopes are currently available to overcome this limitation. The use of fluorescent dyes increases the sensitivity of these microscopes by approximately 10% [9].
Corneal Involvement in HIV-infected Individuals
Published in Ocular Immunology and Inflammation, 2021
Naveen Radhakrishnan, Derrick Smit, N Venkatesh Prajna, Rathinam S.R.
Microsporidia are obligate intracellular parasites closely resembling fungi.42 Intestinal microsporidiosis leading to diarrhea was reported in HIV-infected individuals caused by Encephalitozoon intestinalis and Enterocytozoon bieneusis.43 Microsporidial keratoconjunctivitis was initially reported in HIV-infected individuals. Due to the widespread awareness, more reports of microsporidial keratoconjunctivitis are reported even in non-HIV infected immunocompetent individuals.44 Microsporidial keratoconjunctivitis was first documented in 1990 in an HIV infected patient with chronic follicular conjunctivitis with coarse punctuate epithelial keratopathy (Figure 5). Diagnosis was confirmed by electron microscopy which showed Encephalitozoon cuniculi.45 Microsporidial stromal keratitis by Trachipleastophora anthropthera is also reported in an HIV-infected individual.46 Diagnosis is by calcofluor white stain, grams smear, confocal microscopy and electron microscopy.42 Various drugs have been reported to be useful in the treatment of microsporidial keratitis, namely, fluconazole, PHMB, fumagillin, itraconazole, voriconazole, fluoroquinolones and albendazole.42 In a randomized control trial by Das et al, no significant difference was found in the time to heal and time to cure between patients treated with PHMB and placebo.47 In a study by Agashe et al, 95% of patients had no decrease in the final visual acuity after treatment with topical fluconazole.44
Endogenous Endophthalmitis A Complication of COVID-19 Pandemic: A Case Series
Published in Ocular Immunology and Inflammation, 2021
Manisha Agarwal, Mani Sachdeva, Surendra Pal, Harita Shah, Madhu Kumar R, Alay Banker
Vitreous sample was sent for microbiological examination. Direct microscopy, KOH preparation and calcofluor white stain from the specimen showed the presence of fungal filaments. Specimen was inoculated on SDA and incubated at 25°C and 37°C. The morphology of growth on lactophenol cotton blue stain showed the presence of pale brown pigmented, sympodial, pseudoseptae, fusiform, round ended conidia suggestive of Bipolaris species. (Figure 1c) The patient was kept on a frequent follow-up with continuation of tablet ciprofloxacin 750 mg and tablet voriconazole 200 mg twice daily and he showed gradual progressive improvement. Follow-up at 8 weeks, the right eye visual acuity had improved to 6/12, N8 and the left eye recorded a vision of 6/60 with no evidence of active infection.