Spatial distribution of Mycobacterium tuberculosis mRNA and secreted antigens in acid-fast negative human antemortem and resected tissue.

BACKGROUND: The ability to detect evidence of Mycobacterium tuberculosis (Mtb) infection within human tissues is critical to the study of Mtb physiology, tropism, and spatial distribution within TB lesions. The capacity of the widely-used Ziehl-Neelsen (ZN) staining method for identifying Mtb acid-fast bacilli (AFB) in tissue is highly variable, which can limit detection of Mtb bacilli for research and diagnostic purposes. Here, we sought to circumvent these limitations via detection of Mtb mRNA and secreted antigens in human tuberculous tissue. METHODS: We adapted RNAscope, an RNA in situ hybridisation (RISH) technique, to detect Mtb mRNA in ante- and postmortem human TB tissues and developed a dual ZN/immunohistochemistry staining approach to identify AFB and bacilli producing antigen 85B (Ag85B). FINDINGS: We identified Mtb mRNA within intact and disintegrating bacilli as well as extrabacillary mRNA. Mtb mRNA was distributed zonally within necrotic and non-necrotic granulomas. We also found Mtb mRNA within, and adjacent to, necrotic granulomas in ZN-negative lung tissue and in Ag85B-positive bronchiolar epithelium. Intriguingly, we observed accumulation of Mtb mRNA and Ag85B in the cytoplasm of host cells. Notably, many AFB were negative for Ag85B staining. Mtb mRNA was observed in ZN-negative antemortem lymph node biopsies. INTERPRETATION: RNAscope and dual ZN/immunohistochemistry staining are well-suited for identifying subsets of intact Mtb and/or bacillary remnants in human tissue. RNAscope can identify Mtb mRNA in ZN-negative tissues from patients with TB and may have diagnostic potential in complex TB cases. FUNDING: Wellcome Leap Delta Tissue Program, Wellcome Strategic Core Award, the National Institutes of Health (NIH, USA), the Mary Heersink Institute for Global Health at UAB, the UAB Heersink School of Medicine.

Percutaneous aspiration of aortic valve vegetation in a patient with aortic valve endocarditis.

Key Clinical Message: Percutaneous aspiration for debulking of vegetations in right-sided infective endocarditis has been well-described, however, this technique can be employed successfully for left-sided vegetations in select high-risk patients. Abstract: We report a case of percutaneous aspiration of an aortic valve vegetation in a patient with prosthetic valve endocarditis. This novel approach was selected after patient declined surgical intervention for an enlarging vegetation despite antibiotic therapy. The procedure was successful, resulting in the complete removal of solid vegetation without complications.

Detection of Mycobacterium tuberculosis in human tissue via RNA in situ hybridization.

Rationale: Accurate TB diagnosis is hampered by the variable efficacy of the widely-used Ziehl-Neelsen (ZN) staining method to identify Mycobacterium tuberculosis ( Mtb ) acid-fast bacilli (AFB). Here, we sought to circumvent this current limitation through direct detection of Mtb mRNA. Objectives: To employ RNAscope to determine the spatial distribution of Mtb mRNA within tuberculous human tissue, to appraise ZN-negative tissue from confirmed TB patients, and to provide proof-of-concept of RNAscope as a platform to inform TB diagnosis and Mtb biology. Methods: We examined ante- and postmortem human TB tissue using RNAscope to detect Mtb mRNA and a dual ZN/immunohistochemistry staining approach to identify AFB and bacilli producing antigen 85B (Ag85B). Measurements and main results: We adapted RNAscope for Mtb and identified intact and disintegrated Mtb bacilli and intra- and extracellular Mtb mRNA. Mtb mRNA was distributed zonally within necrotic and non-necrotic granulomas. We also found Mtb mRNA within, and adjacent to, necrotic granulomas in ZN-negative lung tissue and in Ag85B-positive bronchial epithelium. Intriguingly, we observed accumulation of Mtb mRNA and Ag85B in the cytoplasm of host cells. Notably, many AFB were negative for Ag85B staining. Mtb mRNA was observed in ZN-negative antemortem lymph node biopsies. Conclusions: RNAscope has diagnostic potential and can guide therapeutic intervention as it detects Mtb mRNA and morphology in ZN-negative tissues from TB patients, and Mtb mRNA in ZN-negative antemortem biopsies, respectively. Lastly, our data provide evidence that at least two phenotypically distinct populations of Mtb bacilli exist in vivo .

A Review of Cardiac Complications in Coronavirus Disease 2019.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has shown an association with acute myocardial injury, cardiomyopathy, and myocarditis. Individuals with myocardial involvement in association with the coronavirus disease 2019 (COVID-19) may be at increased risk of developing severe illness. Cardiomyopathies are a heterogeneous group of diseases of the myocardium associated with mechanical and/or electrical dysfunction that usually exhibit inappropriate ventricular hypertrophy or dilation and are due to a variety of causes that frequently are genetic. It has been primarily divided into three subsets: genetic, mixed, and acquired cardiomyopathy. We anticipate that, because of the high inflammatory response, other cardiovascular complications may also occur in COVID-19 patients with severe symptoms. This review explores new information as it pertains to COVID-19 and cardiac complications.