3.18 Bartonella Henselae
Microbiology review for the USMLE Step 1 exam
- Bartonella henselae is an intracellular gram negative rod that causes several different diseases
- Bartonella targets and lives inside specialized immune cells called CD34+ cells
- Bartonella creates a protective vacuole that protects it and helps it evade immune detection
- Bartonella henselae is a facultative intracellular bacteria
- Three different clinical syndromes associated with bartonella henselae: cat scratch disease, bacillary angiomatosis in immunocompromised patients, and bacterial endocarditis
- Cat scratch disease presents with cutaneous manifestations at the site of inoculation (warm, red, swollen, with a vesicle) and swollen lymph nodes near the site
- Bacillary angiomatosis symptoms include fever, multiple clustered red or violaceous papules or nodules on the skin and mucosa, and bone pain
- Bacterial endocarditis: Bartonella makes its way into the bloodstream and infects the inner surface of the heart
- Bartonella henselae is hard to culture from blood, usually diagnosed via serology
- Treatment depends on the clinical syndrome presented, cat scratch disease is usually self-limited and doesn't necessarily require antibiotics, bacillary angiomatosis treated with a long 4-month course of either erythromycin or doxycycline.
