Final answer:
Irritable Bowel Syndrome (IBS) is a noninfectious disease linked to changes in the gut microbiota, unlike a yeast infection, C. difficile infection, or stomach flu which are caused by infectious agents.
Step-by-step explanation:
A noninfectious disease that can be linked to changes in the microbiota is Irritable Bowel Syndrome (IBS). Conditions like yeast infection and stomach flu are caused by infectious agents such as Candida and viruses, respectively. In contrast, C. difficile infection is an antibiotic-associated disease caused by the overgrowth of this bacterium due to disruptions in the normal gut microbiota after antibiotic use. However, IBS can be associated with changes in the gut microbiota that are not due to an infectious process, thereby making option C the correct answer.
The normal flora of our digestive systems, including various microorganisms such as bacteria and fungi, plays a crucial role in maintaining our health. Disturbances to this microbiota can cause several health problems. For example, the overgrowth of C. difficile after the use of antibiotics can cause severe gastrointestinal symptoms. Although not an infection, IBS can arise from alterations in the gut microbiota contributing to symptoms like abdominal pain, bloating, and altered bowel habits.