Which bacteria are commonly found in the large intestine?

Escherichia coli is the correct answer because it is a type of bacteria that is a normal component of the intestinal flora found in the large intestine of humans and many animals. It's part of the family of Enterobacteriaceae and plays a crucial role in gut health, aiding in digestion and fermentation processes. While some strains of E. coli can be pathogenic, the non-pathogenic strains are well-adapted to the gut environment and help protect against harmful pathogens by outcompeting them for resources.

In the context of the large intestine, E. coli is one of the predominant species helping to maintain a balanced gut microbiome. This differentiates it significantly from the other bacteria listed, which are not typically found in substantial numbers in the intestinal tract. For instance, Staphylococcus aureus is primarily associated with skin and respiratory infections rather than the gut. Haemophilus influenzae primarily resides in the respiratory tract and is associated with respiratory infections. Neisseria gonorrhoeae is a sexually transmitted bacterium and does not typically inhabit the large intestine.

Thus, the presence of Escherichia coli in the large intestine underscores its significance in human health and the complex ecosystem of gut microbiota.