Which of the following statement is false?
1 Escherichia coli never cause disease.
2. Escherichia coli provide vitamin K for its host.
3. Escherichia coli often exist in mutualistic relationship with human.
4. A disease causing strain of Escherichia coli causes bloody diarrhea.
The correct answer and explanation is:
The false statement is: Escherichia coli never cause disease.
Explanation:
Escherichia coli (E. coli) is a diverse group of bacteria that naturally reside in the intestines of humans and other warm-blooded animals. While most strains of E. coli are harmless and part of a healthy gut microbiota, some strains can be harmful and cause diseases.
- E. coli provides vitamin K for its host: This is true. Non-pathogenic strains of E. coli in the intestines contribute to the synthesis of vitamin K, an essential nutrient for blood clotting, which the host (human) can absorb.
- E. coli often exists in a mutualistic relationship with humans: This is also true. In this relationship, E. coli provides benefits to the host, such as synthesizing vitamins like vitamin K, while the host offers nutrients and a habitat for the bacteria. This mutualistic interaction helps maintain a healthy intestinal microbiota.
- A disease-causing strain of E. coli causes bloody diarrhea: This is correct. Certain pathogenic strains, such as E. coli O157:H7, produce toxins that can damage the lining of the intestines, leading to severe symptoms such as bloody diarrhea, abdominal cramps, and sometimes kidney failure (hemolytic uremic syndrome).
- E. coli never cause disease: This statement is false. Although most strains of E. coli are harmless, some pathogenic strains, such as E. coli O157:H7, can cause serious infections, including gastrointestinal illnesses, urinary tract infections, and even systemic infections. These disease-causing strains produce toxins, such as shiga toxin, that can cause severe damage to the host.
In summary, E. coli is not always harmless. While it is an important part of the normal gut flora, some strains can cause serious diseases, making it crucial to differentiate between pathogenic and non-pathogenic types.