Question Detail
Question
Which of the following is a typical Gram-negative bacterium?
Correct Answer
Option D is the correct answer.
Detailed Explanation
Helicobacter spp. (e.g., H. pylori) are known Gram-negative bacteria. Clostridium, Bacillus, and Streptococcus are all genera of Gram-positive bacteria.
Hint
Recall the Gram stain characteristics of common bacterial genera.