Full text loading...
Chapter 6 : The Natural History and Ecology of Commensal Human Floras
Category: Bacterial Pathogenesis
Ebook: Choose a downloadable PDF or ePub file. Chapter is a downloadable PDF file. File must be downloaded within 48 hours of purchase
It has been estimated that the number of microorganisms living and thriving in or on an average human being exceeds the number of cells making up that human being by an order of magnitude. In order to gain an understanding of the complexity of the human-associated microflora it has to be seen as the complex ecosystem it is. The importance of being able to differentiate various clones in an investigation of the microbial ecology of a human site was amply demonstrated with the use of serotyping to study intestinal Escherichia coli. Corynebacterium xerosis is an accepted member of the normal flora of the human skin, as well as mucocutaneous membranes such as the nasopharynx. Lactobacillus acidophilus and L. fermentum are the most frequently described species inhabiting the human vagina, but there have also been reported isolations of other species, such as L. casei, L. plantarum, L. brevis, L. delbrueckii, L. lactis, L. bulgaricus, L. leichmannii, L. salivarius. This chapter provides an understanding of the microbiological and ecological principles that underlie the distribution of bacteria on the human body. Enterohemorrhagic E. coli, of which only a few bacteria are required to colonize and cause disease, utilizes the colonizing abilities of the commensal E. coli, but with disastrous effects for the host.