Comparison between histochemical and immunohistochemical methods for diagnosis of sporotrichosis

Assessing Phytogenic and Chemogenic Silver Nanoparticles for Antibacterial Activity and Expedited Wound Recuperation

Green silver nanoparticles (AgNPs) possess tremendous promise for diverse applications due to their versatile characteristics. Coriander and other plant extracts have become popular for greenly synthesizing AgNPs as an economical, biocompatible, cost-effective, and environmentally beneficial alternative to chemical processes. In this study, we synthesized AgNPs from coriander leaves and evaluated their antibacterial, anti-inflammatory, antioxidant, and wound-healing acceleration properties in comparison to chemically synthesized AgNPs. The zeta potentials of AgNPs extracted from green and chemical processes were -32.4 mV and -23.4 mV, respectively. TEM images showed a cuboidal shape of green and chemical AgNPs with a diameter of approximately 100 nm. The FTIR spectra of green AgNPs showed an extreme absorption peak at 3401 cm-1, which signifies O-H stretching vibrations, typically linked to hydroxyl groups. In vitro results elaborated that AgNPs from coriander exerted a stronger effect on anti-Klebsiella pneumoniae (KP) through interrupting cell integrity, generating ROS, depleting ATP, and exhibiting significant antioxidant activity, compared with AgNPs synthesized chemically. In vivo experiments showed that AgNPs from coriander, as opposed to chemically manufactured AgNPs, greatly accelerated the healing of wounds contaminated with Klebsiella pneumoniae bacteria by effectively eliminating the bacteria on the wounds and stimulating skin regeneration and the deposition of dense collagen. In vivo assays further demonstrated that green AgNPs effectively enhanced Klebsiella pneumoniae-infected wound healing by extenuating local inflammatory responses and up-regulating VEGF and CD31 expression. In conclusion, green AgNPs significantly alleviated the inflammation without significantly harming the organism.

Novel B-DNA dermatophyte assay for demonstration of canonical DNA in dermatophytes: Histopathologic characterization by artificial intelligence

We describe a novel assay and artificial intelligence-driven histopathologic approach identifying dermatophytes in human skin tissue sections (ie, B-DNA dermatophyte assay) and demonstrate, for the first time, the presence of dermatophytes in tissue using immunohistochemistry to detect canonical right-handed double-stranded (ds) B-DNA. Immunohistochemistry was performed using anti-ds-B-DNA monoclonal antibodies with formalin-fixed paraffin-embedded tissues to determine the presence of dermatophytes. The B-DNA assay resulted in a more accurate identification of dermatophytes, nuclear morphology, dimensions, and gene expression of dermatophytes (ie, optical density values) than periodic acid-Schiff (PAS), Grocott methenamine silver (GMS), or hematoxylin and eosin (H&E) stains. The novel assay guided by artificial intelligence allowed for efficient identification of different types of dermatophytes (eg, hyphae, microconidia, macroconidia, and arthroconidia). Using the B-DNA dermatophyte assay as a clinical tool for diagnosing dermatophytes is an alternative to PAS, GMS, and H&E as a fast and inexpensive way to accurately detect dermatophytosis and reduce the number of false negatives. Our assay resulted in superior identification, sensitivity, life cycle stages, and morphology compared to H&E, PAS, and GMS stains. This method detects a specific structural marker (ie, ds-B-DNA), which can assist with diagnosis of dermatophytes. It represents a significant advantage over methods currently in use.

Immunohistochemical diagnosis of human infectious diseases: a review

BACKGROUND

Immunohistochemistry (IHC) using monoclonal and polyclonal antibodies is a useful diagnostic method for detecting pathogen antigens in fixed tissues, complementing the direct diagnosis of infectious diseases by PCR and culture on fresh tissues. It was first implemented in a seminal publication by Albert Coons in 1941.

MAIN BODY

Of 14,198 publications retrieved from the PubMed, Google, Google Scholar and Science Direct databases up to December 2021, 230 were selected for a review of IHC techniques, protocols and results. The methodological evolutions of IHC and its application to the diagnosis of infectious diseases, more specifically lice-borne diseases, sexually transmitted diseases and skin infections, were critically examined. A total of 59 different pathogens have been detected once in 22 different tissues and organs; and yet non-cultured, fastidious and intracellular pathogens accounted for the vast majority of pathogens detected by IHC. Auto-IHC, incorporating patient serum as the primary antibody, applied to diseased heart valves surgically collected from blood culture-negative endocarditis patients, detected unidentified Gram-positive cocci and microorganisms which were subsequently identified as Coxiella burnetii, Bartonella quintana, Bartonella henselae and Tropheryma whipplei. The application of IHC to ancient tissues dated between the ends of the Ptolemaic period to over 70 years ago, have also contributed to paleomicrobiology diagnoses.

CONCLUSION

IHC plays an important role in diagnostic of infectious diseases in tissue samples. Paleo-auto-IHC derived from auto-IHC, is under development for detecting non-identified pathogens from ancient specimens.

Comparison of the Sensitivity of Three Methods for the Early Diagnosis of Sporotrichosis in Cats

Sporotrichosis is caused by species of fungi within the Sporothrix schenckii complex that infect man and animals. In Rio de Janeiro, Brazil, an epidemic has been observed since 1998, with most of the cases being related to transmission from infected cats. Although the definitive diagnosis of feline sporotrichosis is made by fungal culture, cytopathological and histopathological examinations are used routinely, because the long culture period may delay treatment onset. However, alternative methods are desirable in cases of low fungal burden. Immunohistochemistry (IHC) has been described as a sensitive method for diagnosing human and canine sporotrichosis, but there are no reports of its application to cats. The aim of this study was to analyse the sensitivity of cytopathological examination (Quick Panoptic method), histopathology (Grocott silver stain) and anti-Sporothrix IHC by blinded comparisons, using fungal culture as the reference standard. Samples were collected from 184 cats with sporotrichosis that exhibited skin ulcers. The sensitivities of Grocott silver stain, cytopathological examination and IHC were 91.3%, 87.0% and 88.6%, respectively. Grocott silver stain showed the best performance. IHC showed high sensitivity, as did cytopathological examination and these may be considered as alternative methodologies. When the three methods were combined, the diagnosis was established in 180 (97.8%) out of 184 cases. Taken together, these findings indicate the need to implement these methods as routine tools for the early diagnosis of sporotrichosis in cats, notably when fungal culture is not available.

Características clínico-epidemiológicas, histomorfológicas e histoquímicas da esporotricose felina

Resumo Esporotricose é uma infecção fúngica causada por espécies do complexo Sporothrix, vista com maior frequência em gatos, equinos e cães. Os principais objetivos deste estudo retrospectivo foram caracterizar os aspectos histomorfológicos e histoquímicos da esporotricose em 10 gatos, além de avaliar os aspectos epidemiológicos, clínicos e os achados macroscópicos desses 10 casos, obtidos dos protocolos de biópsias e necropsias dos arquivos do Laboratório de Patologia Veterinária da Universidade Federal de Santa Maria. A doença acometeu predominantemente gatos machos, sem raça definida e apresentou-se principalmente na forma cutânea disseminada. As lesões macroscópicas caracterizaram-se como nódulos cutâneos (ulcerados ou não) e como massas e placas ulceradas. Na histopatologia observou-se uma relação entre a quantidade de leveduras observada e dois padrões de resposta inflamatória. O primeiro padrão caracterizou-se por numerosas leveduras que se encontravam, na sua maioria, no interior de numerosos macrófagos com citoplasma abundante e muitas vezes vacuolizado. Nesse padrão, a quantidade de neutrófilos variava de leve a moderada. O segundo padrão caracterizava-se por numerosas células epitelioides, infiltrado predominantemente acentuado de neutrófilos e a quantidade de leveduras era leve e estas eram observadas geralmente livres no espaço extracelular. As leveduras eram redondas, ovais ou alongadas (em forma de charuto). Foram utilizadas várias técnicas histoquímicas como a impregnação pela prata de Grocott, ácido periódico de Schiff e azul Alciano que facilitaram a visualização, caracterização da morfologia e quantificação dos organismos. A coloração de Giemsa permitiu a visualização do agente, porém não permitiu destacá-los nitidamente de outros elementos intralesionais. Os organismos foram negativos para grânulos de melanina pela coloração de Fontana-Masson em todos os casos. O estudo histomorfológico e histoquímico permitiu demonstrar características fúngicas determinantes para o estabelecimento do diagnóstico de esporotricose através dessa ferramenta diagnóstica.

Driving cartilage formation in high-density human adipose-derived stem cell aggregate and sheet constructs without exogenous growth factor delivery

An attractive cell source for cartilage tissue engineering, human adipose-derived stem cells (hASCs) can be easily expanded and signaled to differentiate into chondrocytes. This study explores the influence of growth factor distribution and release kinetics on cartilage formation within 3D hASC constructs incorporated with transforming growth factor-β1 (TGF-β1)-loaded gelatin microspheres. The amounts of microspheres, TGF-β1 concentration, and polymer degradation rate were varied within hASC aggregates. Microsphere and TGF-β1 loading concentrations were identified that resulted in glycosaminoglycan (GAG) production comparable to those of control aggregates cultured in TGF-β1-containing medium. Self-assembling hASC sheets were then engineered for the production of larger, more clinically relevant constructs. Chondrogenesis was observed in hASC-only sheets cultured with exogenous TGF-β1 at 3 weeks. Importantly, sheets with incorporated TGF-β1-loaded microspheres achieved GAG production similar to sheets treated with exogenous TGF-β1. Cartilage formation was confirmed histologically via observation of cartilage-like morphology and GAG staining. This is the first demonstration of the self-assembly of hASCs into high-density cell sheets capable of forming cartilage in the presence of exogenous TGF-β1 or with TGF-β1-releasing microspheres. Microsphere incorporation may bypass the need for extended in vitro culture, potentially enabling hASC sheets to be implanted more rapidly into defects to regenerate cartilage in vivo.

Rapid identification of Sporothrix schenckii in biopsy tissue by PCR

BACKGROUND

The dimorphic fungus Sporothrix schenckii is the etiological agent of sporotrichosis, an important cutaneous mycosis with a worldwide distribution. At present, it is challenging to rapidly discover and identify Sporothrix schenckii in biopsy tissues nowadays.

AIMS

To explore new methods for rapid diagnosis of sporotrichosis.

MATERIALS AND METHODS

We screened specific primers for Sporothrix schenckii using 50 clinical isolates from patients with sporotrichosis. DNA was extracted from the lesions of 30 cases of clinically suspected sporotrichosis using the Graham s method of CTAB and amplified by PCR using the screened specific primers.

RESULTS

The primer S2-R2 was applicable for the identification of S. schenckii from different geographic areas and clinical types with high specificity and sensitivity. Twenty-five out of the thirty cases (83.3%) amplified using the primer S2-R2 showed positive bands. Further positive bands were observed in 95.6% of cases tested positive by fungal culture.

CONCLUSIONS

Using the PCR technique and specific primers, we developed a new diagnostic method that can rapidly diagnose sporotrichosis with tissues obtained from clinical biopsies.

Proposal of a histopathological predictive rule for the differential diagnosis between American tegumentary leishmaniasis and sporotrichosis skin lesions

BACKGROUND

American tegumentary leishmaniasis (ATL) and sporotrichosis exhibit similar histopathology and low frequencies of microorganism detection.

OBJECTIVES

This study seeks to identify microscopic alterations that can distinguish between these diseases.

METHODS

Haematoxylin and eosin stained slides of 171 ATL and 97 sporotrichosis samples from active cutaneous lesions were examined for histopathological alterations. The lesions were diagnosed by isolating the agent (which was not visible) in culture. An intuitive diagnosis was assigned to each slide. The strength of the association between the histopathological findings and the diagnosis was estimated by an odds ratio, and each finding was graded according to a regression model. A score was assigned to each sample based on the histopathological findings. A study of the interobserver reliability was performed by calculating kappa coefficients of the histopathological findings and intuitive diagnoses.

RESULTS

The markers 'macrophage concentration', 'tuberculoid granuloma' and 'extracellular matrix degeneration' were associated with ATL. 'Suppurative granuloma', 'stellate granuloma', 'different types of giant cells', 'granulomas in granulation tissue' and 'abscess outside the granuloma' were associated with a diagnosis of sporotrichosis. 'Macrophage concentration' and 'suppurative granuloma' had the highest (substantial and almost perfect, respectively) reliability. The regression model score indicated 92.0% accuracy. The intuitive diagnosis had 82.5% diagnostic accuracy and substantial reliability.

CONCLUSIONS

Taking into account the clinical and epidemiological context, some histopathological alterations might be useful for the differential diagnosis between ATL and sporotrichosis cutaneous lesions in cases in which the aetiological agent is not visible.

Evaluation of immunohistochemistry for the diagnosis of sporotrichosis in dogs

The aim of this study was to apply immunohistochemistry (IHC) for the diagnosis of canine sporotrichosis and to compare this method with the Grocott's silver stain (GSS) and periodic acid Schiff (PAS) techniques. Eighty-seven dogs with sporotrichosis (group 1) and 35 with American tegumentary leishmaniosis (ATL) (group 2) were studied. The fungus was detected in group 1 by GSS, PAS and IHC. IHC was also applied to group 2 to evaluate the occurrence of cross-reactions. PAS, GSS and IHC detected yeast cells in 19.5%, 43.7% and 65.5% of the group 1 cases, respectively. The detection of intracellular antigens of Sporothrix schenckii by IHC increased the sensitivity of the histological diagnosis to 80.5%. No positive reaction was observed in ATL lesions. The results suggest that IHC may be indicated for the diagnosis of sporotrichosis because of its higher diagnostic sensitivity.

Comparative histopathological study of sporotrichosis and American tegumentary leishmaniasis in dogs from Rio de Janeiro

Pyogranulomatous lesions from 80 dogs with sporotrichosis and 26 dogs with American tegumentary leishmaniasis (ATL) were compared microscopically in order to identify features that would support the diagnostic suspicion and direct the subsequent search for the aetiological agent of either infection. Odds ratios and their respective 95% confidence intervals were calculated in order to evaluate the impact of the microscopical findings on the diagnosis of either disease. Lesions with well-formed granulomata were 14 times more likely to be due to sporotrichosis than ATL. Marked neutrophil infiltration into granulomata was 12.26 times more likely to be associated with sporotrichosis when compared with lesions having mild neutrophilic infiltration. Absence of lymphocytes and macrophages in the peripheral infiltrate was associated with a 9.71 and 4.93 higher chance, respectively, of being sporotrichosis rather than ATL compared with lesions where these cells were present. Lesions with a perivascular, perifollicular and interstitial peripheral inflammatory infiltrate were 5.48 times more likely to be due to sporotrichosis than ATL when compared with lesions with a diffuse peripheral infiltrate. Histopathological analysis may therefore contribute to the diagnosis of sporotrichosis or ATL skin lesions in dogs since this method permits the identification of features that direct the diagnostic suspicion, thus facilitating the search for the aetiological agent in histological sections, permitting the precise request of subsequent tests and thereby reducing costs and time taken to achieve a definitive diagnosis and the initiation of appropriate therapy.

Asteroid body in sporotrichosis. Yeast viability and biological significance within the host immune response

The asteroid body in Sporotrichosis (AB) is a characteristic structure that allows diagnosis in lymphangitic presentations and whose generation and composition is not fully understood. Our study focused on the biological relationship between the yeast and host elements present in the AB. Indirect immunofluorescence showed that on ABs obtained from naturally infected individuals there were antigenically related IgG and IgM molecules in the spikes of the radiated crowns. However, there were differences in the pattern of distribution for each immunoglobulin isotypes. The yeast cells located at the center of the ABs were viable, as shown by the generation of germ tubes and conidial formation after 36-48 hours of incubation at 22 degrees C. The central yeast could divide and proliferate even in the ABs that had been pre-treated with specific anti-Sporothrix schenckii serum and fresh complement. The data suggests that AB in sporotrichosis might be a resistance structure which uses the host immune molecules to the advantage of the yeast.

Lymphocutaneous and nasal sporotrichosis in a dog from southern Italy: case report

Sporotrichosis is a chronic, granulomatous and usually lymphocutaneous infection of humans and animals caused by the dimorphic fungus, Sporothrix schenckii. This study reports a case of lymphocutaneous and nasal sporotrichosis in a hunting dog with a three month history of non-healing skin lesions. Cytological examination of nasal discharge and of the material collected from ulcerated skin surfaces showed a few cigar-shaped organisms within macrophages. Fungal cultures of nasal and ulcerated skin swabs yielded colonies of S. schenckii. The dog received oral itraconazole but died of unrelated causes. Necropsic examination was not performed.

Endemic sporotrichosis

Although first reported more than a century ago, sporotrichosis, caused by Sporothrix schenckii, still remains a poorly studied disease. Results from recently published studies on sporotrichosis in endemic areas are summarised and assembled with previous findings, providing a comprehensive review that highlights the needs for further research.

The asteroid bodies of sporotrichosis

Some believe that asteroid bodies (AB) in sporotrichosis are nonspecific and are equivalent to the AB of sarcoidosis and other granulomatous diseases. We studied 25 skin biopsy specimens of sporotrichosis in which AB were demonstrated, ten of them with Sporothrix-positive culture. Immunohistochemistry was performed in paraffin-embedded biopsy specimens using an anti-Sporothrix antibody. The same procedures were done with seven biopsy specimens of lobomycosis, which contained AB within giant cells. These did not react with the anti-Sporothrix antibody, and by electron microscopy they displayed filamentous and myelin figures similar to the AB of sarcoidosis. In sporotrichosis, the AB are extracellular eosinophilic structures, 15-35 microm in diameter, and located within abscesses. One to three are found in a section. They consist of a central yeast, surrounded by eosinophilic spicules. The yeast stains with the anti-Sporothrix antibody, while the spicules do not. Therefore, AB in sporotrichosis are specific for disease. Visualization of the spicules alone can lead to the demonstration of the AB in adjacent sections, and thus is a useful clue in the diagnosis of sporotrichosis. Sporotrichotic AB must not be confused with the intracellular AB seen in giant cells of granulomatous reactions, which are filamentous and myelin figures that contain lipid.

Diagnosis of systemic mycoses by specific immunohistochemical tests

Immunohistochemistry has proved to be a powerful tool for the accurate diagnosis of a number of important mycoses in humans and animals, such as aspergillosis, candidosis, cryptococcosis, blastomycosis, coccidioidomycosis, histoplasmosis capsulati and duboisii, paracoccidioidomycosis, fusariosis, pseudallescheriosis (scedosporiosis), sporotrichosis, trichosporonosis, penicilliosis, and zygomycosis (mucormycosis). These techniques are also applicable to pneumocystosis and to non-mycotic infections caused by algae such as protothecosis. Apart from the specificity of immunohistochemistry, the application of fluorochromes is highly effective for the localization of typical or atypical fungal elements in lesions with only few organisms present. Occasionally, a dual aetiology of fungal infections may be suspected on the basis of morphological study, and dual staining techniques have the capacity for resolving this question by simultaneous and differential staining of two fungal species present in a tissue specimen.