🦠microbiology review

Actinobacillus actinomycetemcomitans

Written by the Fiveable Content Team • Last updated August 2025
Written by the Fiveable Content Team • Last updated August 2025

Definition

Actinobacillus actinomycetemcomitans is a gram-negative, facultative anaerobic bacterium. It is commonly associated with periodontitis and can cause systemic infections including endocarditis.

Course connection

Topic 25.2: 25.2 Bacterial Infections of the Circulatory and Lymphatic Systems

Unit 25

5 Must Know Facts For Your Next Test

  1. Actinobacillus actinomycetemcomitans is part of the HACEK group of bacteria known to cause infective endocarditis.
  2. It is often found in the oral cavity, particularly in periodontal pockets.
  3. The bacterium produces leukotoxin, which can destroy white blood cells and contribute to disease progression.
  4. It can spread from oral infections to the bloodstream, leading to serious systemic conditions.
  5. Diagnosis often involves blood cultures and PCR for identification due to its fastidious growth requirements.
Actinobacillus actinomycetemcomitans Definition for Microbiology | Fiveable