What is the current genus name for the saccharolytic group formerly placed within Bacteroides? (Recognize the reclassification of oral anaerobes.)

Difficulty: Easy

Correct Answer: Prevotella

Explanation:

Introduction: Black-pigmented oral anaerobes once grouped under “Bacteroides” were reclassified based on biochemical traits and genetics. This question examines knowledge of the modern names attached to saccharolytic taxa.

Given Data / Assumptions:

  • “Saccharolytic” indicates carbohydrate-fermenting capability.
  • We focus on oral anaerobic rods historically termed “Bacteroides.”

Concept / Approach: Reclassification divided these organisms into Prevotella (saccharolytic) and Porphyromonas (asaccharolytic). Therefore, the saccharolytic group corresponds to Prevotella, while Porphyromonas rely on peptides rather than sugars.

Step-by-Step Solution: Identify trait: saccharolysis implies sugar fermentation. Map trait to genus: saccharolytic → Prevotella; asaccharolytic → Porphyromonas. Select Prevotella as the correct current genus.

Verification / Alternative check: Contemporary oral microbiology references use Prevotella for melaninogenic, sugar-fermenting species such as P. melaninogenica and P. intermedia.

Why Other Options Are Wrong:

  • Porphyromonas: Asaccharolytic; not the saccharolytic group.
  • Bacteroides: Historical umbrella; not the present correct genus for these oral species.
  • None of these: Incorrect because Prevotella fits exactly.

Common Pitfalls: Memorizing names without linking to metabolic traits leads to confusion; remember the saccharolytic vs asaccharolytic split.

Final Answer: Prevotella is the current genus for the saccharolytic group.

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