Which of the following is not a common feature of Shigella spp.?

• A. Lactose fermentation
• B. Non-motility
• C. Producing H2S
• D. Oxidase negatives

Answer: (A)

Shigella spp. are a group of bacteria known for certain distinctive characteristics that help in their identification and differentiation from other members of the Enterobacteriaceae family. One key characteristic of Shigella is that they do not ferment lactose. This lack of lactose fermentation is an important feature that distinguishes Shigella from other enteric bacteria like Escherichia coli, which commonly ferment lactose.

In contrast, the other characteristics mentioned are indeed features of Shigella. They are non-motile, meaning that they do not have flagella and do not exhibit mobility like some other enteric bacteria. Additionally, Shigella species do not produce hydrogen sulfide (H2S) in culture, which is a distinguishing feature compared to some other genera within the Enterobacteriaceae family. Furthermore, Shigella spp. are oxidase negative, indicating that they do not produce the enzyme cytochrome oxidase.

Therefore, the correct answer highlights the distinctive trait of Shigella spp. regarding lactose fermentation, which directly ties to their classification and place within microbiological studies and clinical diagnostics.