Microbiota, conceptual illustration. Illustration of bacteria, viruses and other microbes forming part of a microbial flora. Such microbiota are found on all multicellular organisms, including plants and animals. Examples include the microbiota found on human skin and in human intestines. Some bacteria are non-pathogenic and form part of the normal microbiota. These 'good' bacteria help prevent harmful pathogenic (disease-causing) bacteria from taking hold and causing an infection.