Commentary
Article Outline
[Ann Emerg Med. 2010;55:282-283.]
The above article highlights the reemergence of B quintana infection in the urban homeless population. It appears that infection with B quintana is found exclusively in patients with louse infestation. Risk factors for louse infestation include homelessness, alcoholism, and living in cooler climates.1
Bartonella quintana was first described as the agent that caused trench fever in soldiers of World Wars I and II. It is the most common louse-borne infection, and its reemergence in urban homeless populations was recognized in the early 1990s. Since then, it has been increasingly noted to be a cause of endocarditis, chronic bacteremia, bacillary angiomatosis in the immunosuppressed, and “urban trench fever.”
Bartonella quintana is a fastidious gram-negative rod that is difficult to culture. Cultures are usually positive by 14 days, but it can take as long as 45 days to obtain a result.2 Serology techniques have also been used and can detect acute and resolved infection.
The acute course of urban trench fever is highly variable and may be related to the host's immune response to infection. Some patients develop few symptoms, whereas others develop classic trench fever, consisting of fevers, malaise, headache (often retro-orbital), and bone pain (usually involving the anterior tibia). Occasionally, a transient maculopapular rash can develop as well. Quintan fever, a variant of trench fever that consists of a recurring pattern of febrile episodes of 5 days' duration, punctuated by 5 days without fever, can occur, with each successive episode becoming milder. Although trench fever can result in prolonged disability, death is rare.3
Chronic B quintana bacteremia occurs in 5% to 10% of infected patients. These patients often have few symptoms, are rarely febrile, and can become a reservoir for the bacterium.4 Endocarditis can develop in the setting of chronic bacteremia. Patients diagnosed with B quintana endocarditis are typically middle-aged homeless men with a history of louse infestation and no underlying valvular disease.5 Despite treatment, the majority of afflicted patients will go on to require valve replacement surgery. Chronic bacteremia usually fails to yield detectable serology titers, whereas high titers are observed in patients with endocarditis.
Bacillary angiomatosis was first described in the early years of the HIV epidemic and is a proliferative vascular disease associated with B quintana infection. Lesions are usually observed in immunocompromised patients but can also occur in immunocompetent patients. These vascular lesions are often superficial, dermal, or subcutaneous and can occur as solitary or multiple lesions. These lesions can bleed profusely when traumatized. In addition, bone lesions and subcutaneous masses have also been associated with B quintana infection.3
Treatment for B quintana endocarditis and chronic bacteremia has not been well defined. Challenges in finding effective treatment appear to be related to sequestration of the bacterium in erythrocytes. One clinical trial found that a tetracycline and aminoglycoside combination was associated with improved treatment success.6, 7
In patients at risk for louse infestation, emergency physicians should be aware of the reemergence of B quintana and of the disease processes that can result from B quintana infection. Patients with nonspecific symptoms who may be at risk of B quintana endocarditis should have blood cultures obtained before antimicrobial treatment. Laboratory personnel should be notified that Bartonella is suspected so they can improve the chances of isolating the organism by prolonging the incubation period and using other techniques.
References
- . Preventing and controlling emerging and reemerging transmissible diseases in the homeless. Emerg Infect Dis. 2008;14:1353–1359
- . Natural history of Bartonella infections (an exception to Koch's Postulate). Clin Diagn Lab Immunol. 2002;9:8–18
- . Bartonella quintana characteristics and clinical management. Emerg Infect Dis. 2006;12:217–223
- Chronic Bartonella quintana bacteremia in homeless patients. N Engl J Med. 1999;340:184–189
- Epidemiologic and clinical characteristics of Bartonella quintana and Bartonella henselae endocarditis: a study of 48 patients. Medicine (Baltimore). 2001;80:245–251
- Minireview: recommendations for treatment of human infections caused by Bartonella species. Antimicrob Agents Chemother. 2004;48:1921–1933
- . Randomized open trial of gentamicin and doxycycline for eradication of Bartonella quintana from blood in patients with chronic bacteremia. Antimicrob Agents Chemother. 2003;47:2204–2207
Section editors: David A. Talan, MD; Gregory J. Moran, MD; Robert Pinner, MD
PII: S0196-0644(09)01902-7
doi:10.1016/j.annemergmed.2009.12.030
© 2010 Published by Elsevier Inc.
