Vol. 20, No. 45
THE JOHNS HOPKINS MICROBIOLOGY NEWSLETTER
Tuesday, November 6, 2001
A. Provided by Leslie Edwards Reger, Division of Outbreak Investigation, Maryland Department of Health and Mental Hygiene.
No information available.
B. The Johns Hopkins Hospital, Department of Pathology. Information
provided by Rob Law, M.D.
Case Description
A 26 year old HIV infected male with a CD4 count of 4 cells/mm presented to his PMD with a three month history of malaise, fever, abdominal cramping, and fatigue. He had been recently discharged from an outside hospital with a diagnosis of fever of unknown origin and a hematocrit of 29%. Initial workup revealed a hematocrit of 22%. The patient owns a cat, and reports playing with a friend’s kitten several months ago. Bacterial, AFB, and fungal cultures were all negative. An abdominal CT revealed hepatomegaly with punctate echogenic foci in the liver and spleen, raising the possibility of peliosis hepatis. Empiric therapy was begun. Serologies for Bartonella henselae were positive at 1:256, and a liver biopsy revealed dilated vascular spaces and focal lymphoplasmacytic inflammation. Special stains for organisms were negative.
Bacillary Angiomatosis
Introduction: Bacillary angiomatosis (BA) was first described in 1983 in a patient with HIV. It is the vascular proliferative form of an infection with Bartonella organisms. BA may affect almost any organ system, but most commonly affects skin and subcutaneous tissue.
Organism and epidemiology. Bartonella henselae and Bartonella quintana are small gram-negative rods identified in 1990 and originally classified in the genus Rochalimaea.
Bartonella henselae is harbored both cats and their fleas, Bartonella quintana appears to use humans as a reservoir and the human body louse as the transmission vector. The geographic distribution of BA largely parallels HIV infection. In the USA, approximately 90% of patients with BA are men. BA is extremely rare in children.
Clinical features. BA most commonly manifests as cutaneous lesions, but every organ system can be affected. Lesions may be small or large, many or few, and can occur with or without systemic disease. Cutaneous nodules of BA range from pink to red or purple with smooth, intact, or ulcerated surfaces. The number of lesions appears to reflect the degree of immunosuppression. Patients with overwhelming infection can be covered with many lesions, which may show a propensity to mucocutaneous junctions. Life threatening lesions are tracheal, endobronchial, and esophageal.
In bacillary peliosis, the affected tissue contains blood filled, endothelial
lined cystic structures. Surrounding parenchyma contains a fibromyxoid
stroma with inflammatory cells, clumps of bacilli can be identified by
Warthin-Starry silver staining if treatment has not begun. Bacillary peliosis
hepatitis can cause elevated transaminases; splenic peliosis can cause
catastrophic hemorrhage, and often causes pancytopenia due to sequestration.
Diagnosis and management. Bacillary angiomatosis can be diagnosed serologically, by tissue staining, or by PCR. Blood cultures may yield the organism if incubated at 35° C for 3 weeks or more. Detection of IgG by enzyme immunoassay is also available.
Treatment with erythromycin or tetracycline derivative is favored. Penicillins
and cephalosporins have no activity against Bartonella despite in
vitro susceptibilities. A combination of doxycycline and rifampin may be
used in patients with severe disease who are immunocompromised. For BA
involving only the skin, oral therapy of 8-12 weeks is recommended.
Electron micrograph displaying characteristic trilamellar cell wall
of Bartonella, a gram negative rod.