Which of the following is a common characteristic of Enterobacteriaceae?

• A. Gram-positive cocci
• B. Non-fermentative metabolism
• C. Facultatively anaerobic
• D. Spore-forming

Answer: (C)

The correct choice highlights the nature of Enterobacteriaceae as facultatively anaerobic organisms. This means that these bacteria can thrive in both the presence and absence of oxygen, enabling them to be versatile and adaptable to different environments. This characteristic is significant because it allows them to survive in various host environments, which is relevant for their role in both normal flora and pathogenic contexts.

In contrast, the other options do not accurately describe Enterobacteriaceae. They are not Gram-positive cocci; instead, they are Gram-negative bacilli. While some bacteria may exhibit non-fermentative metabolism, Enterobacteriaceae are primarily known for their ability to ferment carbohydrates. Lastly, these bacteria do not form spores, as most species within this family reproduce through binary fission. Collectively, these points reinforce the importance of understanding the metabolic capabilities and oxygen requirements of Enterobacteriaceae.