ISOLATION OF BARTONELLA (ROCHALIMAEA) HENSELAE - EFFECTS OF METHODS OF BLOOD COLLECTION AND HANDLING

Bartonella (Rochalimaea) henselae causes cat-scratch disease, bacillar y angiomatosis, peliosis hepatis, and fever in humans. B. henselae can be difficult to culture axenically, and as many as 5 weeks may be req uired before colonies are visible. We compared how different methods o f blood collection and handling affect isolation of this pathogen. Blo od specimens from B. henselae-infected cats were collected in both EDT A and Isolator blood-lysis tubes and were subsequently plated onto rab bit blood-brain heart infusion agar by using three different schedules : plating immediately, plating after 24 h at 25 degrees C, and plating after 26 days at -65 degrees C. Colonies were counted 14 and 35 days after plating. Blood collected in tubes containing EDTA, frozen at -65 degrees C, and then plated on blood agar yielded a median of 60,000 C FU/ml, compared with 25,333 CFU/ml after collection in the Isolator tu bes (P < 0.01). Frozen blood yielded the largest number of B. henselae colonies for any of the schedules tested. These results support previ ous observations that the Isolator system is more sensitive than tubes containing EDTA for isolation of B. henselae and suggest that, for ca t blood, collection in tubes containing EDTA and subsequent freezing m ay further improve the sensitivity of detection of B. henselae.