Which of the following is non-pathogenic bacteria of colon ?

Options

A. Escherichia coli
B. Balantidium coli
C. Entamoeba coli
D. Entamobius vermicularis

Explanation

To determine which of the following is a non-pathogenic bacteria of the colon, we need to analyze each option provided:

1. **Escherichia coli (E. coli)**:
- E. coli is a diverse group of bacteria, and while some strains can be pathogenic, many strains are actually non-pathogenic and are part of the normal flora of the human intestine. These non-pathogenic strains can even produce bacteriocins, which are substances that inhibit the growth of similar bacteria, thus helping to maintain a healthy balance in the gut. Therefore, E. coli is considered non-pathogenic.

2. **Baltadenium coli**:
- This bacterium is known to cause inflammation of the intestinal tract. Since it causes disease, it is classified as pathogenic.

3. **Entamoeba coli**:
- This organism is associated with amoebic dysentery, a disease characterized by severe diarrhea and intestinal inflammation. Therefore, it is also pathogenic.

4. **Enterobius vermicularis**:
- This is a parasitic worm that causes enterobiasis (also known as pinworm infection). Since it causes disease, it is classified as pathogenic as well.

After analyzing all the options, we conclude that the only non-pathogenic bacteria of the colon among the given choices is:

**Answer: Escherichia coli (E. coli)**