TY - CHAP M1 - Book, Section TI - Molecular Mechanisms of Microbial Pathogenesis A1 - Pier, Gerald B. A2 - Jameson, J. Larry A2 - Fauci, Anthony S. A2 - Kasper, Dennis L. A2 - Hauser, Stephen L. A2 - Longo, Dan L. A2 - Loscalzo, Joseph PY - 2018 T2 - Harrison's Principles of Internal Medicine, 20e AB - Over the past five decades, molecular studies of the pathogenesis of microorganisms have yielded a torrent of information about the various microbial and host molecules that contribute to the processes of infection and disease. These processes can be classified into several stages: microbial encounter with and entry into the host; microbial growth after entry; avoidance of innate host defenses; tissue invasion and tropism; tissue damage; and transmission to new hosts. Virulence is the measure of an organism’s capacity to cause disease and is a function of the pathogenic factors elaborated by microbes. These factors promote colonization (the simple presence of potentially pathogenic microbes in or on a host), infection (attachment and growth of pathogens and avoidance of host defenses), and disease (often, but not always, the result of activities of secreted toxins or toxic metabolites). In addition, the host’s inflammatory response to infection greatly contributes to disease and its attendant clinical signs and symptoms. A recent explosion of interest in the microbiome (the collection of microbial genomes present in or on mammalian organisms) and the microbiota (the collection of microbes residing in and on mammalian organisms) and their impact on physiology of, susceptibility to, and response to infection and on immune system development has greatly expanded our understanding of host–pathogen interactions. Furthermore, investigations in this field have documented effects of the microbiome on all aspects of animal—and even plant—physiology, greatly increasing our knowledge of the everyday influence of host–microbe interactions on life. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accesspharmacy.mhmedical.com/content.aspx?aid=1155964032 ER -