What is one significant characteristic that distinguishes E. coli from other non-pathogenic Enterobacteriaceae?

What is one significant characteristic that distinguishes E. coli from other non-pathogenic Enterobacteriaceae?

• A. It cannot ferment lactose
• B. It produces gas during glucose fermentation
• C. It is motile
• D. It forms large colonies on agar

Answer: (B)

E. coli is distinguished from other non-pathogenic Enterobacteriaceae primarily by its ability to produce gas during glucose fermentation. This characteristic is significant because gas production is often used as a diagnostic feature in microbiological testing to identify and differentiate bacterial species. When E. coli ferments glucose, it produces both acid and gas, which can be observed in a laboratory setting, typically through a Durham tube that captures the gas bubbles. This ability to ferment glucose and produce gas is not universally shared among all non-pathogenic Enterobacteriaceae, making it a key differentiating factor. In various types of media, such as phenol red glucose broth, the resultant gas formation signals a positive fermentation reaction specific to E. coli. While lactose fermentation, motility, and colony size are relevant characteristics, they do not singularly distinguish E. coli in the same way that gas production during glucose fermentation does. Therefore, the ability to produce gas when fermenting glucose is a significant and distinctive characteristic of E. coli that aids in its identification.

E. coli is distinguished from other non-pathogenic Enterobacteriaceae primarily by its ability to produce gas during glucose fermentation. This characteristic is significant because gas production is often used as a diagnostic feature in microbiological testing to identify and differentiate bacterial species. When E. coli ferments glucose, it produces both acid and gas, which can be observed in a laboratory setting, typically through a Durham tube that captures the gas bubbles.

This ability to ferment glucose and produce gas is not universally shared among all non-pathogenic Enterobacteriaceae, making it a key differentiating factor. In various types of media, such as phenol red glucose broth, the resultant gas formation signals a positive fermentation reaction specific to E. coli.

While lactose fermentation, motility, and colony size are relevant characteristics, they do not singularly distinguish E. coli in the same way that gas production during glucose fermentation does. Therefore, the ability to produce gas when fermenting glucose is a significant and distinctive characteristic of E. coli that aids in its identification.