Coliform vs. Coliforms

Attribute	Coliform	Coliforms
Definition	A single bacterium belonging to the coliform group	A group of bacteria that includes various species such as E. coli and Klebsiella
Presence	Can be found in water, soil, and the intestines of warm-blooded animals	Commonly found in the intestines of warm-blooded animals and in the environment
Indicator	Used as an indicator of fecal contamination in water	Used as an indicator of overall water quality and potential presence of pathogens
Species	Refers to a specific bacterium	Refers to a group of bacteria

Definition

Coliform bacteria are a group of bacteria that are commonly found in the environment, including in soil, water, and on plants. They are used as indicators of fecal contamination and are often used to assess the safety of drinking water. Coliforms, on the other hand, are a specific subset of coliform bacteria that are used as indicators of water quality. They are typically found in the intestines of warm-blooded animals and are excreted in feces.

Characteristics

Coliform bacteria are gram-negative, rod-shaped bacteria that are capable of fermenting lactose. They are facultative anaerobes, meaning they can grow in the presence or absence of oxygen. Coliforms, on the other hand, are a subset of coliform bacteria that are defined by their ability to ferment lactose within 48 hours at 35°C. This distinguishes them from other coliform bacteria that may not have this specific characteristic.

Presence in the Environment

Coliform bacteria are widespread in the environment and can be found in soil, water, and on plants. They are also commonly found in the intestines of warm-blooded animals. Coliforms, on the other hand, are specifically used as indicators of water quality. They are often found in surface water sources, such as rivers and lakes, and can indicate the presence of fecal contamination.

Health Implications

Coliform bacteria are not necessarily harmful themselves, but their presence can indicate the potential for fecal contamination and the presence of other harmful pathogens. In drinking water, the presence of coliform bacteria can be a sign of inadequate treatment or contamination from sewage or animal waste. Coliforms, on the other hand, are specifically used as indicators of water quality and can help identify potential sources of contamination.

Regulatory Standards

Coliform bacteria are regulated by the Environmental Protection Agency (EPA) as indicators of water quality. The EPA has established maximum contaminant levels for coliform bacteria in drinking water to ensure the safety of public water supplies. Coliforms, on the other hand, are specifically used as indicators of water quality and are not regulated in the same way as coliform bacteria.

Testing Methods

Coliform bacteria are typically detected using a variety of testing methods, including membrane filtration, multiple tube fermentation, and enzyme substrate tests. These methods can help determine the presence and concentration of coliform bacteria in water samples. Coliforms, on the other hand, are specifically identified using the most probable number (MPN) method, which involves inoculating water samples into a series of tubes containing a lactose broth and observing for gas production.

Conclusion

While coliform bacteria and coliforms are related in that they are both used as indicators of water quality, they have distinct characteristics and purposes. Coliform bacteria are a broader group of bacteria that are commonly found in the environment, while coliforms are a specific subset of coliform bacteria that are used as indicators of fecal contamination. Understanding the differences between coliform bacteria and coliforms is important for assessing water quality and ensuring the safety of drinking water sources.