Pathogens causing blood culture negative endocarditis
| Organism | Risk factors for infection |
|---|---|
| Coxiella burnetii (intracellular) 28–37% of BCNE15,17 | Occupational exposure to farm animals (sheep, cattle, goats)18 Living downwind from farms and infected farm material (straw manure) Abattoir workers Laboratory exposure to pathogens Immunosuppression possibly including HIV19 |
| Bartonella henselae (intracellular) | Contact with cats (higher bacteraemia in kittens)20 |
| Bartonella quintana (intracellular) Bartonella spp collectively 12–28% of BCNE15,17 | Contact with human body lice / homeless shelters Chronic alcoholism Travel to north Africa |
| Brucella (fastidious Gram-negative bacilli) Only in endemic areas | Occupational exposure to farm animals (sheep, cattle, goats) Ingesting unpasteurised milk/cheese / undercooked meat Travel to Middle East |
| Fungi 1–2% of BCNE15,17 | HIV positive Indwelling venous catheter Prior cardiac surgery |
| Tropheryma whipplei Up to 6% of BCNE15,17,21 | Occupational exposure to soil / farm animals |
| Tuberculosis and other mycobacteria | Tuberculosis contact or exposure Mycobacterium chimera following cardiac surgery |
BCNE = blood culture negative endocarditis.