Library · Physiology
The microbiota that protects you
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The normal flora is made up of the microorganisms that routinely live in the body, and they are not inert passengers: they influence the host's anatomy, physiology, susceptibility to pathogens, meaning how easily a microbe can make you sick, and morbidity, that is, how much disease the host itself develops.
One of the ways they can help is by occupying the ground first. Those microorganisms outcompete pathogens such as Salmonella for microenvironments, or they produce nutrients useful to the host. It is a place where there is no room left for latecomers.
That effect was measured in animals. With the flora reduced by streptomycin, an antibiotic, fewer than 10 Salmonella were enough to cause an intestinal infection in those animals, whereas normally close to a million are needed.
That does not make the flora harmless. Although it can inhibit pathogens, many of its own members can also cause disease.
In brief
Normal flora influences the host's anatomy, physiology, susceptibility to pathogens, and morbidity.
Its microorganisms can help by outcompeting pathogens such as Salmonella for microenvironments, or by producing nutrients useful to the host.
A place where there is no room left for whoever arrives late.
In animals whose flora was reduced with streptomycin, fewer than 10 Salmonella were enough to cause intestinal infection; normally close to a million are needed.
Although the flora can inhibit pathogens, many of its members can also cause disease.
Sources (1)
- Medical Microbiology, 4th edition, University of Texas Medical Branch at Galveston, NCBI BookshelfNormal Flora, Medical MicrobiologyPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated