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United States Department of Agriculture

Agricultural Research Service

Title: Ecological Aspects of Host Colonization: Coaggregation, Osmoadaptation, and Acid Tolerance Or Resistance (Virulence Mechanisms of Bacterial Pathogens, 3rd ED.)

item Stanton, Thaddeus

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: November 5, 1999
Publication Date: N/A

Technical Abstract: To successfully colonize a host, a bacterium must reach a suitable microhabitat on or within the host, establish dividing cell populations, and persist. A pathogenic bacterium has the additional task of damaging host tissues, inadvertently, or in the course of accomplishing the other steps. Each colonization step requires that characteristics of the bacterium overcome, or at least balance, environmental forces working against the bacterium. Through evolution, adaptations have developed that enable a bacterium to take advantage of or to contend with factors in its environment. Colonization is the successful outcome of bacterial interactions with the living and non-living components of the environment. For the host-associated bacterium, the living components of its environment are host tissues and frequently, but not always, other colonizing micro-organisms. The non-living components can include fluid flow, pH, osmolality, oxygen/redox potential, inert surfaces/viscous matrices (mucus), essential substrates or nutrients, toxicants, bacteriophages. In this chapter, three examples of adaptations important for bacteria colonizing human hosts are described. Coaggregation refers to specific physical associations that occur between bacterial species colonizing the human mouth. Acid resistance and osmoadaptation are features of Helicobacter pylori and E. coli, bacteria that colonize, respectively, the stomach and lower gastrointestinal tract. The chapter is intended to provide a short preview of each topic, not a review.

Last Modified: 4/17/2015
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