American Board of Internal Medicine (ABIM) Certification Practice Exam

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Prepare for the ABIM Certification Exam with multiple choice questions and detailed explanations. Strengthen understanding with flashcards, hints, and thorough review materials. Ace your test!

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What type of bacteria is described as being gram-positive, rod-shaped, and partially acid-fast?

  1. Streptococcus

  2. Nocardia

  3. Mycobacterium

  4. Bacillus

The correct answer is: Nocardia

The characteristics of being gram-positive, rod-shaped, and partially acid-fast specifically describe Nocardia. These bacteria are part of a group that exhibits unique properties due to the presence of mycolic acids in their cell walls, which is a trait associated with acid-fastness. While Mycobacterium is also acid-fast and rod-shaped, it is typically fully acid-fast rather than partially. Streptococcus is spherical and not rod-shaped, and Bacillus, while it is rod-shaped and gram-positive, is not considered acid-fast. Thus, recognizing Nocardia's unique combination of traits as partially acid-fast and its rod shape provides a clear identification of this particular bacterial type.