Background: Bacillary angiomatosis is characterized by vascular lesions, which occur usually in patients infected with the human immunodeficiency virus (HIV). A newly described gram-negative organism, Rochalimaea henselae, has been associated with cutaneous bacillary angiomatosis, but no organism has been isolated and cultivated directly from cutaneous tissue.
Methods: We used two methods to isolate the infecting bacterium from four HIV-infected patients with cutaneous lesions suggestive of bacillary angiomatosis: cultivation with eukaryotic tissue-culture monolayers and direct plating of homogenized tissue onto agar. The patients' blood was cultured with the lysis-centrifugation method. Isolates recovered from skin and blood were identified by sequencing all or part of the 16S ribosomal RNA gene amplified with the polymerase chain reaction.
Results: R. quintana, historically known as the agent of trench fever, was isolated from cutaneous lesions in three patients, after tissue homogenates were cultivated with endothelial-cell monolayers; R. henselae was isolated from a cutaneous lesion in one patient. In two patients, R. quintana was isolated from both cutaneous tissue and blood; in one patient it was also isolated from bone.
Conclusions: In bacillary angiomatosis, either of two species of rochalimaea--R. quintana or R. henselae--can be isolated from cutaneous lesions or blood, providing an additional method of diagnosis.