Host–pathogen interactionThe host–pathogen interaction is defined as how microbes or viruses sustain themselves within host organisms on a molecular, cellular, organismal or population level. This term is most commonly used to refer to disease-causing microorganisms although they may not cause illness in all hosts. Because of this, the definition has been expanded to how known pathogens survive within their host, whether they cause disease or not.
Streptococcus thermophilusStreptococcus thermophilus formerly known as Streptococcus salivarius subsp. thermophilus is a gram-positive bacterium, and a fermentative facultative anaerobe, of the viridans group. It tests negative for cytochrome, oxidase, and catalase, and positive for alpha-hemolytic activity. It is non-motile and does not form endospores. S. thermophilus is fimbriated. It is also classified as a lactic acid bacterium. S. thermophilus is found in fermented milk products and is generally used in the production of yogurt, alongside Lactobacillus delbrueckii subsp.