RT Book, Section A1 Pier, Gerald B. A2 Kasper, Dennis L. A2 Fauci, Anthony S. SR Print(0) ID 1141404324 T1 MOLECULAR MECHANISMS OF MICROBIAL PATHOGENESIS T2 Harrison's Infectious Diseases, 3e YR 2017 FD 2017 PB McGraw-Hill Education PP New York, NY SN 9781259835971 LK accessbiomedicalscience.mhmedical.com/content.aspx?aid=1141404324 RD 2024/03/29 AB Over the past four decades, molecular studies of the pathogenesis of microorganisms have yielded an explosion 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. The recent surge of interest in the role of the microbiota and its associated microbiome—the collection of microbial genomes residing in or on mammalian organisms—in the physiology of, susceptibility to, and response to infection and in immune system development has had an enormous impact on our understanding of host-pathogen interaction.