Which of the following is characteristic of Helicobacter pylori?

Helicobacter pylori is a curved motile Gram-negative rod that is well-known for its role in causing gastric ulcers and chronic gastritis. This bacterium is characterized by its unique spiral shape, which aids in its motility and ability to navigate through the viscous environment of the stomach mucus layer. The flagella, which are tail-like structures, allow H. pylori to move in a corkscrew motion, facilitating its colonization of the gastric epithelium.

Being Gram-negative means that H. pylori has a thin peptidoglycan layer between its inner and outer membranes, which is significant in its identification and affects its staining properties during laboratory testing. The curved shape of H. pylori is also indicative of its classification within the Campylobacteraceae family.

In contrast, other characteristics mentioned in the choices do not apply to Helicobacter pylori. For instance, it is neither nonmotile nor a spore-forming organism, nor is it classified as a non-fermentative rod. Understanding these characteristics is essential for microbiological identification and clinical diagnosis regarding H. pylori infections.