Francisella sp., a Close Relative of Francisella orientalis , Causing Septicemia with Cholestatic Hepatitis in a Patient with Anti-Interferon-γ (IFN-γ) Autoantibodies.

Francisella is an intracellular, fastidious, Gram-negative bacterium that is difficult to identify using routine microbiological methods in the laboratory. We studied the isolation of Francisella sp. (strain IDAMR664) from the blood of a patient with anti-interferon-γ (IFN-γ) autoantibodies who presented with septicemia and cholestatic hepatitis. Analysis of the strain IDAMR664 genome sequence revealed the isolate was closely related to the strain GA01-2794 that had been isolated from a human in the USA. In addition, it was clustered with F. orientalis , a fish pathogen. The isolate contained several virulence factors and had Francisella pathogenicity island pattern no. 3.