What type of bacteria serves as an indicator for potential contamination in water supplies?

Coliform bacteria serve as a crucial indicator for potential contamination in water supplies. They are a broad class of bacteria commonly found in the environment, especially in soil, vegetation, and the intestines of warm-blooded animals. The presence of coliforms in water suggests that there may be fecal contamination and, therefore, a risk of pathogenic organisms entering the water supply.

Coliform bacteria are used in water quality testing because they are easy to detect, and their presence indicates that more harmful pathogens, such as viruses or bacteria that can cause disease, might also be present. This makes them an essential tool for assessing the microbiological quality of drinking water and for public health monitoring.

The other options, while they include some organisms that can be harmful, do not serve as the primary indicator of water contamination in the same way. For example, Escherichia coli is a specific type of coliform and is indeed a fecal indicator, but coliform bacteria encompass a wider range of species. Salmonella and Staphylococcus are pathogenic bacteria that usually indicate specific types of contamination but are not used as general indicators for water quality testing.