HACEK bacilli

Definition

HACEK bacilli are a group of Gram-negative bacteria that are part of the normal flora in the human respiratory and urogenital tracts. They are known for causing endocarditis, particularly in patients with underlying heart conditions.

5 Must Know Facts For Your Next Test

1. HACEK is an acronym for Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, and Kingella.
2. These bacteria are fastidious and require special culture conditions to grow in the laboratory.
3. HACEK organisms are a common cause of culture-negative endocarditis due to their slow growth.
4. Infections with HACEK bacilli often require prolonged antibiotic therapy, typically involving beta-lactam antibiotics.
5. While rare, HACEK infections can lead to serious complications such as emboli or heart valve damage.

Review Questions

• What does the acronym HACEK stand for?
• Why are HACEK organisms difficult to culture in a standard lab setting?
• What type of infections are commonly caused by HACEK bacilli?

Related terms

Endocarditis: Inflammation of the inner layer of the heart, often involving the heart valves.

Gram-Negative Bacteria: Bacteria that do not retain the crystal violet stain used in Gram staining; they appear red or pink under a microscope.

Beta-Lactam Antibiotics: A class of antibiotics that include penicillin and its derivatives; they inhibit bacterial cell wall synthesis.