Andreas Oberbach1, Maik Friedrich2, Stefanie Lehmann3, Nadine Schlichting4, Yvonne Kullnick5, Sandra Gräber6, Tilo Buschmann5, Christian Hagl7, Erik Bagaev8. 1. Department of Cardiac Surgery, Ludwig-Maximilians-University, Munich, Germany; Department of Diagnostics, Fraunhofer Institute for Cell Therapy and Immunology, Leipzig, Germany; Division of Gastroenterology and Hepatology, Department of Medicine, The Johns Hopkins Medical Institutions, Baltimore, Md. Electronic address: Andreas.Oberbach@medizin.uni-leipzig.de. 2. Department of Diagnostics, Fraunhofer Institute for Cell Therapy and Immunology, Leipzig, Germany; Institute of Clinical Immunology, University of Leipzig, Leipzig, Germany. 3. Department of Diagnostics, Fraunhofer Institute for Cell Therapy and Immunology, Leipzig, Germany; Department of Internal Medicine, University of Leipzig, Leipzig, Germany. 4. Department of Diagnostics, Fraunhofer Institute for Cell Therapy and Immunology, Leipzig, Germany; Department of Visceral, Transplantation, Thoracic and Vascular Surgery, Leipzig University Hospital, Leipzig, Germany. 5. Department of Diagnostics, Fraunhofer Institute for Cell Therapy and Immunology, Leipzig, Germany. 6. Institute for Medical Microbiology and Epidemiology of Infectious Diseases, Leipzig University Hospital, Leipzig, Germany. 7. Department of Cardiac Surgery, Ludwig-Maximilians-University, Munich, Germany; Munich Heart Alliance, Partner Site German Center for Cardiovascular Disease (DZHK), Munich, Germany. 8. Department of Cardiac Surgery, Ludwig-Maximilians-University, Munich, Germany.
Abstract
OBJECTIVES: The pathology of structural valvular heart disease (sVHD) ranges from basic diseases of rheumatologic origin to chronic degenerative remodeling processes after acute bacterial infections. Molecular genetic methods allow detection of the complete microbial spectrum in heart valve tissues independent of microbiological cultivation. In particular, whole-metagenome analysis is a sensitive and highly specific analytical method that allows a deeper insight into the pathogenicity of the diseases. In the present study we assessed the pathogen spectrum in heart valve tissue from 25 sVHD patients using molecular and microbiological methods. METHODS: Twenty-five sVHD patients were selected randomly from an observational cohort study (March 2016 to January 2017). The explanted native heart valves were examined using microbiological methods and immunohistological structural analysis. In addition, the bacterial metagenome of the heart valve tissue was determined using next-generation sequencing. RESULTS: The use of sonication as a pretreatment of valve tissue from 4 sVHD patients permitted successful detection of Clostridium difficile, Enterococcus faecalis, Staphylococcus saccharolyticus, and Staphylococcus haemolyticus using microbial cultivation. Histological staining revealed intramural localization. Metagenome analysis identified a higher rate of bacterial infiltration in 52% of cases. The pathogen spectrum included both gram-positive and gram-negative bacteria. CONCLUSIONS: Microbiological and molecular biological studies are necessary to detect the spectrum of bacteria in a calcified heart valve. Metagenome analysis is a valid method to gain new insight into the polymicrobial pathophysiology of sVHD. Our results suggest that an undetected proportion of sVHD might be triggered by chronic inflammation or influenced by secondary bacterial infiltration.
OBJECTIVES: The pathology of structural valvular heart disease (sVHD) ranges from basic diseases of rheumatologic origin to chronic degenerative remodeling processes after acute bacterial infections. Molecular genetic methods allow detection of the complete microbial spectrum in heart valve tissues independent of microbiological cultivation. In particular, whole-metagenome analysis is a sensitive and highly specific analytical method that allows a deeper insight into the pathogenicity of the diseases. In the present study we assessed the pathogen spectrum in heart valve tissue from 25 sVHD patients using molecular and microbiological methods. METHODS: Twenty-five sVHD patients were selected randomly from an observational cohort study (March 2016 to January 2017). The explanted native heart valves were examined using microbiological methods and immunohistological structural analysis. In addition, the bacterial metagenome of the heart valve tissue was determined using next-generation sequencing. RESULTS: The use of sonication as a pretreatment of valve tissue from 4 sVHD patients permitted successful detection of Clostridium difficile, Enterococcus faecalis, Staphylococcus saccharolyticus, and Staphylococcus haemolyticus using microbial cultivation. Histological staining revealed intramural localization. Metagenome analysis identified a higher rate of bacterial infiltration in 52% of cases. The pathogen spectrum included both gram-positive and gram-negative bacteria. CONCLUSIONS: Microbiological and molecular biological studies are necessary to detect the spectrum of bacteria in a calcified heart valve. Metagenome analysis is a valid method to gain new insight into the polymicrobial pathophysiology of sVHD. Our results suggest that an undetected proportion of sVHD might be triggered by chronic inflammation or influenced by secondary bacterial infiltration.
Authors: Charlotte M Ahle; Kristian Stødkilde; Mastaneh Afshar; Anja Poehlein; Lesley A Ogilvie; Bo Söderquist; Jennifer Hüpeden; Holger Brüggemann Journal: Microorganisms Date: 2020-07-23