Non-HACEK gram-negative bacillus endocarditis.

Area of Science:

• Infectious Diseases
• Cardiology
• Microbiology

Background:

• Infective endocarditis (IE) caused by non-HACEK (non-Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella species) gram-negative bacilli is rare and poorly understood.
• It is often misperceived as primarily affecting injection drug users.

Purpose of the Study:

• To characterize the clinical presentation and outcomes of patients with non-HACEK gram-negative bacillus endocarditis.
• To compare these characteristics within a large, international, contemporary patient cohort.

Main Methods:

• Utilized data from the International Collaboration on Infective Endocarditis Prospective Cohort Study (ICE-PCS).
• Included hospitalized patients with definite endocarditis across 61 hospitals in 28 countries.
• Described and compared non-HACEK gram-negative bacillus endocarditis cases with those caused by other pathogens.

Main Results:

• Out of 2761 patients, 49 (1.8%) had non-HACEK gram-negative bacillus endocarditis, predominantly on prosthetic valves (29 cases).
• Escherichia coli and Pseudomonas aeruginosa were the most common pathogens.
• Most infections (57%) were health care-associated, with injection drug use being rare (4%).
• Endovascular devices were more frequent in this group (29% vs. 11%).
• In-hospital mortality was high at 24%, despite 51% undergoing cardiac surgery.

Conclusions:

• Non-HACEK gram-negative bacillus endocarditis is predominantly associated with health care exposure, challenging the notion that it primarily affects injection drug users.
• Limitations include small numbers per treatment group and lack of long-term follow-up, hindering definitive treatment recommendations.