For Health Care Providers

Diagnosis

• CSD may be diagnosed presumptively in patients with typical signs and symptoms and a compatible exposure history. Serology can confirm the diagnosis, although cross-reactivity may limit interpretation in some circumstances. In general, lymph node aspiration is not recommended except to relieve severe pain and swelling or in cases where the diagnosis is unclear.
  • B. henselae DNA may be detected by PCR or culture of lymph node aspirates or blood, though sensitivity of these methods is not optimal for blood samples.
  • Since B. henselae is a fastidious, slow-growing bacterium, cultures should be held for a minimum of 21 days.
• Trench fever can be diagnosed by isolation of B. quintana from blood cultured on blood or chocolate agar under 5% CO₂. Microcolonies can be seen after 21 days of incubation at 37°C.
  • Trench fever can also be diagnosed by serology.
• Carrión’s disease is typically diagnosed via blood culture or direct observation of the bacilli in peripheral blood smears during the acute phase of infection (Oroya fever).
• Endocarditis due to Bartonella species can be diagnosed by serology and by PCR or culture of excised heart valve tissue.

Treatment

The use of antibiotics to shorten the course of disease is debated. Most cases of cat scratch disease (CSD) resolve without treatment, although some patients may develop complications from disseminated disease. Azithromycin has been shown to decrease lymph node volume more rapidly compared to no treatment. The recommended dose of azithromycin for CSD is:

• For adults and children > 45.5 kg: 500 mg on day 1, followed by 250 mg for 4 days
• For children ≤ 45.5 kg: 10 mg/kg on day 1, followed by 5 mg/kg for 4 days

A number of other antibiotics are effective against Bartonella infections, including penicillins, tetracyclines, cephalosporins, and aminoglycosides. Since aminoglycosides are bactericidal, they are typically used as first-line treatment for Bartonella infections other than CSD. Often, with serious infections, more than one antibiotic is used.

Trench fever, Carrión’s disease, and endocarditis due to Bartonella spp. are serious infections that require antibiotic treatment. Health care providers should consult with an expert in infectious diseases regarding treatment options.

Treatment References

• Angelakis E, Raoult D. Pathogenicity and treatment of Bartonella infections. Int J Antimicrob Agents 2014;44:16–25.
• Rolain JM, Brouqui P, Koehler JE, Maguina C, Dolan MJ, Raoult D. Recommendations for treatment of human infections caused by Bartonella species. Antimicrob Agents Chemother 2004;48:1921-33.