What is the Difference Between Coliform and Enterobacteriaceae

The main difference between coliform and Enterobacteriaceae is that a coliform is a group of bacteria in the family of Enterobacteriaceae that form gas and acid by lactose fermentation, whereas Enterobacteriaceae is a large family of Gram-negative bacteria, consisting of symbionts to pathogens.

Coliform and Enterobacteriaceae are two groups of Gram-negative bacteria. They are enteric bacteria and some members of them live in the intestine of animals.

Key Areas Covered

1. What is Coliform
   • Definition, Characteristics, Importance
2. What is Enterobacteriaceae
   • Definition, Characteristics, Importance
3. Similarities Between Coliform and Enterobacteriaceae
   • Outline of Common Features
4. Difference Between Coliform and Enterobacteriaceae
   • Comparison with Key Differences

Key Terms

Coliform, Enterobacteriaceae

What is Coliform

Coliform is Gram-negative oxidase negative, non-spore-forming, aerobic, or facultative anaerobic rod-shaped bacteria. Although the coliform group is not a taxonomic group, functionally it contains bacteria that ferment lactose to produce both gas and acid at 35 °C. Citrobacter, Enterobacter, Escherichia, and Klebsiella are types of coliform bacteria.

Figure 1: E. coli

Furthermore, many coliform bacteria occur in the intestines of humans and animals. However, most occur naturally in soil and water. E. coli is the major coliform bacteria that occur in the human intestine. Moreover, coliform bacteria are important as an indicator of low sanitary quality of foods, milk, and water. A positive coliform test does not necessarily indicate contamination. Generally, coliform tests are done for water and for milk in the dairy industry.

What is Enterobacteriaceae

Enterobacteriaceae is a family of Gram-negative bacteria. This group of bacteria includes 30 genera and over 100 species. However, these bacteria contain both harmless symbiotic bacteria as well as familiar pathogens such as Salmonella, Escherichia coli, Klebsiella, and Shigella. In addition, the most significant feature of Enterobacteriaceae is that they can live in the intestine of animals.

Figure 2: Enterobacteriaceae

Moreover, Enterobacteriaceae is a rod-shaped (bacilli) bacterium with a 1–5 μm length. They appear medium to large-sized, gray colonies on blood agar. Significantly, most of the Enterobacteriaceae bacteria have flagella. On the other hand, they are non-spore forming. Metabolism—wise, Enterobacteriaceae are facultative anaerobes that undergo fermentation of sugars to produce lactic acids and various other end products. This is due to the presence of the enzyme, β-galactosidase. In addition, most Enterobacteriaceae are normal members of the gut microbiota of animals and humans. Other forms occur in soil and water and are parasitic on animals and plants. Escherichia coli, one of the Enterobacteriaceae is the model organism in genetics and biochemistry.

Similarities Between Coliform and Enterobacteriaceae

• Coliform and Enterobacteriaceae are two types of Gram-negative bacteria.
• They are rod-shaped bacteria.
• Some members of these bacteria can live in the intestine of animals.
• Generally, they live in the soil and on vegetation.
• Moreover, both groups have flagella for their movement.

Difference Between Coliform and Enterobacteriaceae

Definition

Coliform refers to belonging to a group of rod-shaped bacteria typified by E. coli while Enterobacteriaceae refers to a large family of gram-negative straight bacterial rods (order Enterobacteriales) that ferment glucose with the production of acid or acid and gas and that includes the common coliform organisms and a number of serious pathogens of humans, lower animals, and plants.

Significance

Usually, coliforms are a type of Enterobacteriaceae while Enterobacteriaceae is a group of rod-shaped bacteria.

Fermentation

Coliform undergoes lactose fermentation while Enterobacteriaceae undergoes glucose fermentation. 

Pathogenicity

Coliforms are non-pathogenic bacteria while Enterobacteriaceae can be pathogenic.

Conclusion

In brief, coliform and Enterobacteriaceae are two groups of Gram-negative bacteria that are facultative anaerobes. They undergo fermentation of sugars due to the presence of the enzyme, β-galactosidase. Coliform bacteria undergo lactic acid fermentation, fermenting lactose while other Enterobacteriaceae undergo glucose fermentation. Moreover, coliform and other Enterobacteriaceae are enteric bacteria that can live in the intestine of animals. More importantly, coliform is not pathogenic while Enterobacteriaceae are pathogenic. Therefore, the main difference between coliform and Enterobacteriaceae is their fermentation.

References:

1. Coliform bacterium. Coliform Bacterium – an overview | ScienceDirect Topics. (n.d.). Retrieved September 19, 2022.
2. Wikimedia Foundation. (2022, August 15). Enterobacteriaceae. Wikipedia. Retrieved September 19, 2022.

Image Courtesy:

1. “E coli at 10000x, original” By fkfkrErbe – Own work (Public Domain) via Commons Wikimedia
2. “Citrobacter freundii” By Kookaburra – Own Work (Public Domain) via Commons Wikimedia