Abstract
Agrobacterium radiobacter biovar 2 was repeatedly grown from the blood of an elderly patient receiving artificial ventilation and broad-spectrum antibiotics. No source of the organism was found, but the septicemia ceased when cefotaxime was given. Sera from the patient showed a fourfold rise in antibody against the organism and higher titers than sera from all but 1 of 50 healthy blood donors. The organism did not contain the plasmid associated with plant oncogenicity. This case may be only the second in which Agrobacterium sp. has been clearly linked with human infection.