Enterobacteriaceae- Definition, Characteristics, Identification


Enterobacteriaceae is a large and diverse family of bacteria that includes many well-known pathogens, such as Escherichia coli, Salmonella, Shigella, and Yersinia. These bacteria are Gram-negative, meaning that they have a thin cell wall that does not retain the purple dye in the Gram stain technique. They are also rod-shaped (bacilli) and usually have flagella that enable them to move. Most of them are facultatively anaerobic, which means that they can grow with or without oxygen. They can also ferment sugars to produce acids and gases, and they can reduce nitrate to nitrite.

Enterobacteriaceae are widely distributed in nature and can be found in soil, water, plants, and animals. Some of them are part of the normal flora of the intestine of humans and other animals, where they help with digestion and vitamin synthesis. However, some of them can also cause infections and diseases in humans and animals, especially when they enter other parts of the body or when they acquire antibiotic resistance or virulence factors. Some of the common diseases caused by Enterobacteriaceae are diarrhea, dysentery, urinary tract infections, septicemia, wound infections, and plague.

Enterobacteriaceae are classified into different genera based on their phenotypic and genotypic characteristics. Some of the criteria used for classification are the presence or absence of certain enzymes (such as indole, urease, oxidase), the ability to ferment different sugars (such as lactose, sucrose, mannitol), the production of gas from glucose fermentation, the motility, and the antigenic structure (such as O, H, and K antigens). Currently, there are more than 30 genera and over 100 species in the Enterobacteriaceae family.

In this article, we will discuss the habitat and ecology, classification, characteristics, pathogenicity, and identification of Enterobacteriaceae.