Bilateral periorbital necrotising fasciitis associated with invasive group: a Streptococcus infection

A previously independent 56-year-old immunocompetent woman presented with septic shock in the setting of periorbital swelling and diffuse infiltrates on chest imaging. Blood cultures were positive for growth of group A Streptococcus (GAS). Broad spectrum antimicrobials were initiated with the inclusion of the antitoxin agent clindamycin. Necrosis of periorbital tissue was noted and surgical consultation was obtained. Débridement of both eyelids with skin grafting was performed. GAS was isolated from wound cultures and also observed on periorbital tissue microscopy. The final diagnosis was bilateral periorbital necrotising fasciitis (PONF) associated with invasive GAS infection. The patient had a prolonged intensive care unit course with input from multiple specialist teams. This case demonstrates the importance of early recognition and treatment of PONF, the profound systemic morbidity caused by these infections, and illustrates successful multidisciplinary teamwork.

Feature-rich covalent stains for super-resolution and cleared tissue fluorescence microscopy

Fluorescence microscopy is a workhorse tool in biomedical imaging but often poses substantial challenges to practitioners in achieving bright or uniform labeling. In addition, while antibodies are effective specific labels, their reproducibility is often inconsistent, and they are difficult to use when staining thick specimens. We report the use of conventional, commercially available fluorescent dyes for rapid and intense covalent labeling of proteins and carbohydrates in super-resolution (expansion) microscopy and cleared tissue microscopy. This approach, which we refer to as Fluorescent Labeling of Abundant Reactive Entities (FLARE), produces simple and robust stains that are modern equivalents of classic small-molecule histology stains. It efficiently reveals a wealth of key landmarks in cells and tissues under different fixation or sample processing conditions and is compatible with immunolabeling of proteins and in situ hybridization labeling of nucleic acids.

Multiscale 3-dimensional pathology findings of COVID-19 diseased lung using high-resolution cleared tissue microscopy

The study of pulmonary samples from individuals who have died as a direct result of COVID-19 infection is vital to our understanding of the pathogenesis of this disease. Histopathologic studies of lung tissue from autopsy of patients with COVID-19 specific mortality are only just emerging. All existing reports have relied on traditional 2-dimensional slide-based histological methods for specimen preparation. However, emerging methods for high-resolution, massively multiscale imaging of tissue microstructure using fluorescence labeling and tissue clearing methods enable the acquisition of tissue histology in 3-dimensions, that could open new insights into the nature of SARS-Cov-2 infection and COVID-19 disease processes. In this article, we present the first 3-dimensional images of lung autopsy tissues taken from a COVID-19 patient, including 3D “virtual histology” of cubic-millimeter volumes of the diseased lung, providing unique insights into disease processes contributing to mortality that could inform frontline treatment decisions.

PATHOMORPHOLOGICAL CHANGES IN THE SKIN OF THE GUINEA PIGS IN THE COURSE OF MICROSPORES

During the course of microspores on the skin, the balance between the species of saprophytic microorganisms and hypersensitivity as an integral part of the inflammatory reaction resulting from the presence of the pathogen in the skin is disturbed. The degree of expression of inflammation varies. Clinical manifestations of microsporia are manifested by erythema, alopecia, scaly and crust formation. The aim. Histological studies were performed to determine pathomorphological changes in the skin of guinea pigs during microsporia. The studies were conducted on clinically healthy and sick guinea pigs during the acute course of the disease, during regeneration and during recovery.And also carry out a description and characterization of the identified changes in the skin.The obtained research results showed that patients with microsporia had changes in the morphological composition of the skin, which were characterized by thickening and keratinization of the epidermis, there were small-focal polymorphic cell infiltrates, there was a violation of the microvasculature and the formation of micellar formations. Materials and methods. The material for histological examination(pieces of guinea pig skin) was fixed in a 10–12 % cooled solution of neutral formalin, followed by pouring into paraffin according to the scheme proposed by G.A. Merkulov (1969). Histomic sections 5–7 μm thick were made on the MC-2 dome microtome. Hematoxylin and eosin staining were used for the morphological evaluation of cells and tissue. Microscopy was performed using an OLIMPUS CX-41 microscope. Results. Signs of superficial inflammation with hyperkeratosis and desquamation of cells of the stratified epithelium, microcracks of the epidermis were found in the skin of the patient with microsporia of the tentacle during the acute course. Signs of inflammation of the follicles and surrounding tissues are visualized. Round-cell and plasma connective tissue infiltrates of the connective tissue of the skin were detected by lymphoid, histiocytic and other cellular elements. There is moderate leukocyte infiltration in the dermis. Signs of inflammation by type of infiltration around the hair follicles, enlargement of the blood capillaries and the presence of microabscesses. In the stage of regeneration during recovery, a clear contoured layer of epithelial cells is established. There are no signs of inflammatory reaction in the dermis. Conclusion. In microspores, inflammatory processes occur in all layers of the skin. The skin of sick animals loses its barrier function due to pathomorphological changes. The long-term consequences of the pathological process during the course of microspores can provoke the development of chronic dermatitis with scleroderma. During the course of microspores on the skin, the balance between the species of saprophytic microorganisms and hypersensitivity as an integral part of the inflammatory reaction resulting from the presence of the pathogen in the skin is disturbed. The degree of expression of inflammation varies. Clinical manifestations of microsporia are manifested by erythema, alopecia, scaly and crust formation. The aim. Histological studies were performed to determine pathomorphological changes in the skin of guinea pigs during microsporia. The studies were conducted on clinically healthy and sick guinea pigs during the acute course of the disease, during regeneration and during recovery.And also carry out a description and characterization of the identified changes in the skin.The obtained research results showed that patients with microsporia had changes in the morphological composition of the skin, which were characterized by thickening and keratinization of the epidermis, there were small-focal polymorphic cell infiltrates, there was a violation of the microvasculature and the formation of micellar formations.Materials and methods. The material for histological examination(pieces of guinea pig skin) was fixed in a 10–12 % cooled solution of neutral formalin, followed by pouring into paraffin according to the scheme proposed by G.A. Merkulov (1969). Histomic sections 5–7 μm thick were made on the MC-2 dome microtome. Hematoxylin and eosin staining were used for the morphological evaluation of cells and tissue. Microscopy was performed using an OLIMPUS CX-41 microscope. Results. Signs of superficial inflammation with hyperkeratosis and desquamation of cells of the stratified epithelium, microcracks of the epidermis were found in the skin of the patient with microsporia of the tentacle during the acute course. Signs of inflammation of the follicles and surrounding tissues are visualized. Round-cell and plasma connective tissue infiltrates of the connective tissue of the skin were detected by lymphoid, histiocytic and other cellular elements. There is moderate leukocyte infiltration in the dermis. Signs of inflammation by type of infiltration around the hair follicles, enlargement of the blood capillaries and the presence of microabscesses. In the stage of regeneration during recovery, a clear contoured layer of epithelial cells is established. There are no signs of inflammatory reaction in the dermis. Conclusion. In microspores, inflammatory processes occur in all layers of the skin. The skin of sick animals loses its barrier function due to pathomorphological changes. The long-term consequences of the pathological process during the course of microspores can provoke the development of chronic dermatitis with scleroderma.

Case 47

Mucormycosis can mimic aspergillosis, both clinically and radiologically. High-risk patient groups include those with acute myeloid leukaemia, following stem cell transplantation, solid organ transplantation, and poorly controlled diabetes mellitus, such as diabetic ketoacidosis against a background of poor social conditions. Persistent symptoms of sinusitis in an at-risk patient, should suggest rhinocerebral mucormycosis. Direct tissue microscopy with specialized stains (e.g. Grocot) is the mainstay of diagnosis but pan-fungal PCR assays are being evaluated. Aggressive debridement, which sometimes needs to be repeated, together with antifungal agents such as amphotericin B and/or, increasingly, posaconazole often for months, are required in the management of this challenging infection. However, the outcome is often dependant on the underlying condition, degree of immunosuppression, and whether it can be reduced.