AST Surgical Technologist Practice Exam

Which organism is a normal resident flora of the intestinal tract?

1. Staphylococcus aureus

2. Escherichia coli

3. Clostridium difficile

4. Salmonella

The correct answer is: Escherichia coli

Escherichia coli is indeed recognized as a normal resident flora of the intestinal tract. This bacterium plays a crucial role in the gut ecosystem, where it helps in the digestion of food, synthesizes certain vitamins, and contributes to the overall health of the intestinal environment. The presence of E. coli in the gastrointestinal tract is typically harmless and can be beneficial; however, some strains can lead to gastrointestinal illnesses under different conditions. In a healthy setting, E. coli is part of a balanced microbiome that supports bodily functions. The other organisms listed are not normal residents of the intestinal tract in the same beneficial way. Staphylococcus aureus, for instance, is more commonly associated with skin infections and can cause harmful diseases when it enters the body through breaks in the skin. Clostridium difficile, on the other hand, is often responsible for serious intestinal infections, particularly following antibiotic use, and is not considered a normal part of intestinal flora. Lastly, Salmonella is typically pathogenic and associated with foodborne illness, not as a resident flora. Thus, the presence of Escherichia coli in the intestinal tract highlights its important role in maintaining gut health.