Section 19.1 Animal bodies are favorable environments for the growth of many microorganisms, including pathogens. The initial colonization by a pathogen is on the surface of the host, often on the mucous membranes. The skin is a dry, acidic environment that is not conducive to the growth of most microorganisms. However, the Gram-positive Bacteria and other members of the skin normal flora, colonize the sweat glands. Describe the properties of microorganisms that grow well on the skin.
Bacteria can grow on tooth surfaces in thick layers called plaque.
The microorganisms in plaque produce adherent substances that encourage further colonization. Acid-producing organisms in plaque damage tooth surfaces, and dental caries form. A variety of microorganisms can contribute to caries and peridontal disease. The stomach is very acidic, and is a barrier to most microbial growth. The intestinal tract is slightly acid to neutral, and supports large, diverse population of microorganisms in a variety of nutritional and environmental conditions.