Probable new species of Desulfovibrio isolated from a pyogenic liver abscess.

A fastidious, slowly growing, spiral gram-negative bacterium was isolated from the liver abscess of an 82-year-old man with a 3-week history of febrile illness. The organism was an obligate anaerobe that grew at 37 and 42 degrees C but not at 25 degrees C. Its vibrioid or spiral morphology on Gram staining, rapid progressive motility, electron micrograph features, and biochemical tests were all consistent with the organism belonging to the genus Desulfovibrio. 16S rRNA gene sequencing of this organism demonstrated a 97% similarity to Desulfovibrio desulfuricans with 45 nucleotide differences, suggesting that it is a new species of Desulfovibrio.