Francisella tularensis bacteremia

Abstract

Bacteremia caused by Francisella tularensis is rare and has been reported mainly in the United States and infrequently in Europe. We report herein the first case of bacteremic F. tularensis pneumonia in an immunocompetent individual in southern Europe.

FIG. 1.

(a) PCR products of the F. tularensis 17-kDa lipoprotein gene (250 bp) (27). PCR products that migrated in a 1% agarose gel were stained with ethidium bromide. Lanes: 1 and 4, strain isolated from our patient; 2, negative control (Escherichia coli K-12); 3, positive control (F. tularensis clinical isolate; Institut Pasteur); 5, molecular size markers (φX174 RF DNA/HaeIII fragments of 1,358, 1,078, 872, 603, 310, 281, 271, 234, 194, 118, and 72 bp [from top to bottom]). (b) Western blots of whole-cell lysates from F. tularensis strains with antiserum against F. tularensis 43-kDa protein (2). Samples were separated by sodium dodecyl sulfate-polyacrylamide electrophoresis in a 12.5% gel, blotted onto nitrocellulose, probed with rabbit anti-43-kDa antibodies, and incubated with an anti-rabbit IgG conjugated with peroxidase. Lanes 1, F. tularensis clinical isolate (Institut Pasteur); 2, F. tularensis strain isolated from a tick (Institut Pasteur); 3, strain isolated from our patient; 4, molecular size protein standards (212, 107, 69, 43, 28.6, 19, and 15.5 kDa [from top to bottom]; Gibco).

FIG. 2.

Western blot analysis showing the antibody responses to 17- and 43-kDa F. tularensis proteins in the serum from our patient 2 months after the onset of infection. Supernatants of whole-cell sonicates from F. tularensis (lane 1, F. tularensis clinical isolate [Institut Pasteur]; lane 2, F. tularensis strain isolated from a tick [Institut Pasteur]; lane 3, strain isolated from our patient) were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, blotted with the patient's serum, and incubated with peroxidase-conjugated anti-human antibodies. Lane 4 contains molecular size protein standards (212, 107, 69, 43, 28.6, 19, and 15.5 kDa [from top to bottom]; Gibco).