Introduction of this organism, often as part of an aerosol of potable water into the alveolus of the lung, results in the microorganism's finding a new niche in the macrophage instead of in its usual host Acanthamoeba or Hartmanella . More absorbent tampons helped select for a new disease, toxic shock syndrome. While pathogenic traits of the disease-causing microbes are of consequence, humans and their technology and social behavior have played a major role in providing pathogenic microbes with new venues for their wares. Food poisoning by Escherichia coli O157, Campylobacter , and Salmonella emerged more from food technology and food distribution networks than from any fundamental change in the virulence properties of the bacteria. In a sense, we have provided these bacteria with a moveable feast.
Medicine views pathogens as microorganisms capable of causing disease.
The emphasis is on disease, not the microorganism. However, from the microbial standpoint, being pathogenic is a strategy for survival and simply one more remarkable example of the extraordinary diversity of the microbial world. Humans are a home to a myriad of other living creatures. From mouth to anus, from head to toes, every millimeter of our cells exposed to the outside world is inhabited by a rich biology. From the mites that may inhabit the eyebrows to the seething cauldron of more than 600 species of bacteria that inhabit the large bowel, we are a veritable garden of microorganisms.