HACEK Group: Understanding Fastidious Bacteria and Their Role in Infective Endocarditis


◉ Introduction

The HACEK group is a collection of Gram-negative bacteria often associated with systemic infections, particularly infective endocarditis. The acronym HACEK stands for the following genera: Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, and Kingella. Although rare, these bacteria account for approximately 1-3% of infective endocarditis cases, a serious condition requiring prompt and appropriate management.

◉ General Characteristics of the HACEK Group

HACEK group bacteria share several common features:

◉ Members of the HACEK Group

Haemophilus:

Aggregatibacter:

Cardiobacterium:

Eikenella:

Kingella:

◉ Diagnosis

Diagnosis of HACEK infections relies on:

1. Blood Cultures: HACEK bacteria are fastidious and may require specific culture conditions for growth. For example:

2. PCR (Polymerase Chain Reaction): A rapid and sensitive method to detect bacterial DNA, especially when blood cultures are negative or delayed.

3. Echocardiography: To assess valve damage and confirm endocarditis diagnosis.

◉ Conclusion

Though rare, the HACEK group represents a significant cause of infective endocarditis, particularly in at-risk patients (prosthetic valves, heart disease). Rapid management combining precise microbiological diagnosis (adapted blood cultures, targeted PCR) and appropriate antibiotic therapy is essential to improve patient outcomes. Future research should focus on pathogenic mechanisms and optimizing therapeutic strategies.