Infection with Bartonella weissii and detection of Nanobacterium antigens in a North Carolina beef herd

Very recently, Bartonella organisms have been isolated from large ruminants (deer, elk, and dairy and beef cattle) located in the United States and in France. In this study, we report the serologic, microbiologic, and molecul ar findings related to the isolation of a Bartonella species in North Carol ina beef cattle and the detection of nanobacterial antigen using a commerci ally available enzyme-linked immunosorbent assay. Between August 1998 and S eptember 1999, blood was collected from 38 tattle ranging in age from 1 mon th to 6.5 years. After a 1-month incubation period, a Bartonella sp. was is olated on a 5% rabbit blood agar plate from three of six EDTA blood samples . PCR amplification of the 16S rRNA gene from all three isolates resulted i n a DNA sequence that was 100% identical to that of B. weissii 16S rRNA (Ge nBank no. AF199502). By IFA testing, 36 of 38 cattle had antibodies (greate r than or equal to1:64) to Bartonella weissii (bovine origin) antigens. Nan obacterial antigen was detected in 22 of 22 serum samples. We conclude that infection with an organism similar or closely related to B. weissii can oc cur in North Carolina cattle and that although their actual existence is st ill controversial Nanobacterium antigens were detected with a commercially available test kit. The epidemiology, vector biology, and potential pathoge nicity of these organisms in cattle deserve future consideration.