This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and health, Subject name: Social & Preventive Medicine
The following organism because of its easy culture methods is widely used as bacteriology indicator of water pollution- 
Select and explain. 
A. Foecal streptococci, B. Escherichia coli, C. Clostridium perfringes, D. Salmonella Typhi
B: Escherichia coli
Answer: B: Escherichia coli 
Explanation: Coliform oarganisms are used as indicators of faecal pollution rather than the water borne pathogens because: Coliform organisms are constantly present in abundance in human intestine. They are easily detected by culture methods as small as one bacteria in 100 ml of water whereas other methods of detecting pathogens are complicated and time consuming. They survive longer than pathogens They have greater resistance to forces of natural purification than the water borne pathogens. Parks textbook of preventive and social medicine.K Park. Edition 23.Pg no: 721