1. Explain what is meant by indicator organisms when testing a water sample.
2. What are the media to determine the presence of the indicator organisms?
3. What are the morphological and biochemical characteristics of theses indicator organisms?
4. Discuss the three major species of Staphlococcus. Explain why one of them is more pathogenic compared to the other two species. Which factor determines the pathogeneisis of the organism?
1) Explain what is meant by indicator organisms when testing a water sample.
An indicator organism is one that is used to measure potential contamination of environmental sources like water. These organisms are not necessarily harmful themselves, but may indicate that other harmful organisms are present. These organisms are used because they are easy, inexpensive, and reliable to test for. There are several types:
1. Coliforms - Bacteria that are naturally present in the environment, but should not be present in treated water. They are not harmful, but indicate that other problems may be present.
2. Fecal coliform and E.Coli - Indicate that water may be contaminated with human or animal fecal matter (solid waste).
3. Fecal indicators (Enterococci or coliphage) - Same as point 2. Note that coliphage is a virus. These are of particular concern to young children and the elderly.
This solution looks at water quality testing and explores the definitions of indicator organisms as well as there role in understanding and defining water quality and sanitation.