Which organism NOT inhibited by the reactive nitrogen species generated in this oral context?

Which organism NOT inhibited by the reactive nitrogen species generated in this oral context?

• A. Porphyromonas gingivalis
• B. S. mutans
• C. Aggregatibacter actinomycetemcomitans
• D. Enterococcus faecalis

Answer: (A)

Reactive nitrogen species in the mouth create nitrosative stress that damages bacterial proteins, DNA, and membranes. Bacteria vary in how well they cope with that stress, depending on their detoxification and repair abilities. Porphyromonas gingivalis often withstands nitrosative stress better because it has effective defenses that neutralize NO and limit nitrosative damage, allowing it to persist even when others are inhibited. The other organisms listed generally lack these robust defenses in this context, making them more susceptible to inhibition by reactive nitrogen species. So, the organism not inhibited by these reactive nitrogen species here is Porphyromonas gingivalis.

Reactive nitrogen species in the mouth create nitrosative stress that damages bacterial proteins, DNA, and membranes. Bacteria vary in how well they cope with that stress, depending on their detoxification and repair abilities. Porphyromonas gingivalis often withstands nitrosative stress better because it has effective defenses that neutralize NO and limit nitrosative damage, allowing it to persist even when others are inhibited. The other organisms listed generally lack these robust defenses in this context, making them more susceptible to inhibition by reactive nitrogen species. So, the organism not inhibited by these reactive nitrogen species here is Porphyromonas gingivalis.