Grocott Methenamine Silver Staining Is the Optimal Approach to Histological Diagnosis of Pulmonary Cryptococcosis

Wang, Suijing; Lai, Jieyi; Wu, Ruibin; Zhang, Lihong; Huang, Mayan; Xiao, Yue; Zhang, Xinke; Chen, Jiewei

doi:10.3389/fmicb.2022.885511

Cited by 11 publications

(5 citation statements)

References 16 publications

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“…2 ), we hypothesized that urease-dependent increase in lung pH would similarly promote melanization in vivo. Unfortunately, silver-based stains do not reliably distinguish melanized from non-melanized C. neoformans cells because the stains also react with polysaccharides in the cell wall 18 , 19 . Despite this limitation, it was possible to discern deeply pigmented C. neoformans cells from the surrounding tissue in hematoxylin and eosin (H & E) stained sections of infected Galleria mellonella 20 .…”

Section: Resultsmentioning

confidence: 99%

Reciprocal modulation of ammonia and melanin production has implications for cryptococcal virulence

Baker

Casadevall

2023

Nat Commun

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The fungus Cryptococcus neoformans is the causative agent of cryptococcosis, a disease that is uniformly lethal unless treated with antifungal drugs, yet current regimens are hindered by host toxicity and pathogen resistance. An attractive alternative approach to combat this deadly disease is the direct targeting of pathogen-derived virulence mechanisms. C. neoformans expresses multiple virulence factors that have been studied previously as isolated entities. Among these, are urease, which increases phagosomal pH and promotes brain invasion, and melanization, which protects against immune cells and antifungal treatments. Here we report a reciprocal interdependency between these two virulence factors. Cells hydrolyzing urea release ammonia gas which acts at a distance to raise pH and increase melanization rates for nearby cells, which in turn reduces secretion of urease-carrying extracellular vesicles. This reciprocal relationship manifests as an emergent property that may explain why targeting isolated virulence mechanisms for drug development has been difficult and argues for a more holistic approach that considers the virulence composite.

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Section: Resultsmentioning

confidence: 99%

Reciprocal modulation of ammonia and melanin production has implications for cryptococcal virulence

Baker

Casadevall

2023

Nat Commun

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“…61 Staining with Grocott-Gomori methenamine silver, periodic acid-Schiff, Alcian blue, and mucicarmine is employed to identify the fungus. 1,62 In pulmonary cryptococcosis, Grocott-Gomori methenamine silver staining is the most used and has shown 100% sensitivity, significantly higher than periodic acid-Schiff staining when compared to Alcian blue staining. 62 Our review identified that Grocott-Gomori methenamine silver and mucicarmine staining were the most employed in the diagnosis.…”

Section: Discussionmentioning

confidence: 99%

“…1,62 In pulmonary cryptococcosis, Grocott-Gomori methenamine silver staining is the most used and has shown 100% sensitivity, significantly higher than periodic acid-Schiff staining when compared to Alcian blue staining. 62 Our review identified that Grocott-Gomori methenamine silver and mucicarmine staining were the most employed in the diagnosis. 17,21,22,[24][25][26][28][29][30][31]33,34,[36][37][38]40,41 Additionally, Fontana-Masson staining, which identifies melanin in the yeast cell wall, has also been used, but less frequently.…”

Section: Discussionmentioning

confidence: 99%

Orofacial Cryptococcosis: A Challenging Clinical Report and a Systematic Analysis of the Literature

et al. 2023

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Cryptococcosis is a neglected fungal disease. The scarcity of studies on oral cryptococcosis is certainly due to rarity and/or underreporting of the disease, especially in Brazil. We describe an example of orofacial cryptococcosis affecting a 57-year-old man after heart transplantation, who presented with multiple erythematous ulcers and erosions distributed in the chin, nasal cavity, labial mucosa, hard palate, and buccal vestibule. Computed tomography revealed opacities and micronodules in the lungs. Histopathological features of the oral and pulmonary lesions were compatible with Cryptococcus spp. Amphotericin B and fluconazole were used for treatment during hospitalization and itraconazole for prolonged therapy after hospital discharge. The patient has been under follow up for 6 months without signs of disease. According to a review conducted in PubMed, Web of Science, Scopus, Embase, and LILACS for data analysis of oral cryptococcosis, 26 reports were described in the literature. Predilection for men was observed (85%), with a male:female ratio of 5.5:1. The mean age of the individuals was 49 ± 15.3 years. Oral cryptococcosis mostly presented as an ulcer ( n = 17). The palate and tongue were the most affected sites ( n = 9 for each). Amphotericin B was the primary therapy utilized in most patients. Seventeen (65%) individuals survived. Knowledge of the clinicodemographic aspects of oral cryptococcosis is important for clinicians in decision making and surveillance.

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“…Specific stainings that are applied for a more detailed analysis of CN/CG include Indian ink, Hematoxylin and Eosin, and Periodic Acid-Shiff stainings [49,205,206]. In par-ticular, the capsule is targeted by some of these stainings [207].…”

Section: Ex Vivo Methodologymentioning

confidence: 99%

Preclinical Models for Cryptococcosis of the CNS and Their Characterization Using In Vivo Imaging Techniques

Roosen,

Maes,

Musetta

et al. 2024

JoF

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Infections caused by Cryptococcus neoformans and Cryptococcus gattii remain a challenge to our healthcare systems as they are still difficult to treat. In order to improve treatment success, in particular for infections that have disseminated to the central nervous system, a better understanding of the disease is needed, addressing questions like how it evolves from a pulmonary to a brain disease and how novel treatment approaches can be developed and validated. This requires not only clinical research and research on the microorganisms in a laboratory environment but also preclinical models in order to study cryptococci in the host. We provide an overview of available preclinical models, with particular emphasis on models of cryptococcosis in rodents. In order to further improve the characterization of rodent models, in particular the dynamic aspects of disease manifestation, development, and ultimate treatment, preclinical in vivo imaging methods are increasingly used, mainly in research for oncological, neurological, and cardiac diseases. In vivo imaging applications for fungal infections are rather sparse. A second aspect of this review is how research on models of cryptococcosis can benefit from in vivo imaging methods that not only provide information on morphology and tissue structure but also on function, metabolism, and cellular properties in a non-invasive way.

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Grocott Methenamine Silver Staining Is the Optimal Approach to Histological Diagnosis of Pulmonary Cryptococcosis

Cited by 11 publications

References 16 publications

Reciprocal modulation of ammonia and melanin production has implications for cryptococcal virulence

Reciprocal modulation of ammonia and melanin production has implications for cryptococcal virulence

Orofacial Cryptococcosis: A Challenging Clinical Report and a Systematic Analysis of the Literature

Preclinical Models for Cryptococcosis of the CNS and Their Characterization Using In Vivo Imaging Techniques

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