From the Guidelines
The treatment of active Bartonella infection typically involves antibiotic therapy with azithromycin 500mg on day one followed by 250mg daily for 5 days as the first-line option, as supported by a double-blind placebo-controlled study 1.
Key Considerations
- The choice of antibiotic should be based on the severity of the infection and the patient's immune status.
- For more severe infections or in immunocompromised patients, combination therapy may be necessary, often adding rifampin to the azithromycin regimen.
- Alternative antibiotics include doxycycline, ciprofloxacin, or trimethoprim-sulfamethoxazole (TMP-SMX), all typically for 2-4 weeks depending on clinical response.
- For Bartonella endocarditis or severe systemic disease, intravenous therapy with gentamicin may be combined with oral azithromycin for a total of 6 weeks, as recommended by guidelines for the management of patients with valvular heart disease 1.
Treatment Approach
- Patients should be monitored for symptom improvement, and follow-up testing may be necessary to confirm clearance of the infection.
- Bartonella bacteria can establish intracellular infections, which is why antibiotics with good intracellular penetration like azithromycin are preferred.
- Treatment should be adjusted based on clinical response, with longer durations needed for immunocompromised patients or those with complications like endocarditis or neuroretinitis.
Important Considerations
- The diagnosis of Bartonella infections may be difficult because the organism is fastidious and difficult to grow in culture, and serological testing may show cross-reactivity between different species of Bartonella 1.
- A positive Warthin-Starry silver stain of infected lymph node tissue is useful to confirm the diagnosis, although it cannot differentiate species of Bartonella 1.
From the FDA Drug Label
Bartonellosis due to Bartonella bacilliformis. The treatment of active Bartonella infection is doxycycline (PO), as it is indicated for the treatment of Bartonellosis caused by Bartonella bacilliformis 2.
- Key points:
- Doxycycline is the recommended treatment
- Bartonella bacilliformis is the specific species mentioned in the drug label
- No other Bartonella species are mentioned in the label.
From the Research
Treatment Options for Active Bartonella Infection
The treatment of active Bartonella infection, also known as bartonellosis, depends on the severity of the disease and the patient's immune status.
- For patients with Bartonella lymphadenopathy, antibiotics do not significantly affect the cure rate 3.
- Patients with Bartonella spp. bacteraemia should be treated with gentamicin and doxycycline, while chloramphenicol has been proposed for the treatment of B. bacilliformis bacteraemia 4.
- Gentamicin in combination with doxycycline is considered the best treatment regimen for endocarditis 4.
- Erythromycin is the first-line antibiotic therapy for the treatment of angioproliferative lesions 4.
- Rifampicin or streptomycin can be used to treat verruga peruana 4.
Antibiotic Susceptibility
The antibiotic susceptibility of Bartonella spp. can vary depending on the growth medium and intracellular environment.
- In the standard insect media, none of the antibiotics tested were effective in inhibiting the growth of Bartonella sp. 5.
- In the BAPGM enrichment media, all antibiotics tested had minimum inhibitory concentrations (MICs) below 0.5 µg/mL 5.
- Azlocillin was the most potent antibiotic, with a MIC of 0.01 µg/mL 5.
- When Bartonella was tested under intracellular growth conditions, none of the antibiotics were efficacious singly, but growth inhibition was observed when azlocillin and azithromycin were combined 5.
Emerging Treatment Options
Recent studies have identified FDA-approved drugs with activity against stationary phase Bartonella henselae.
- These include pyrvinium pamoate, daptomycin, methylene blue, azole drugs, aminoglycosides, and others 6.
- These drugs have shown higher activity against stationary phase B. henselae than the current frontline antibiotic erythromycin 6.
- Further research is needed to develop more effective treatments for persistent Bartonella infections.