Bacteremia in a patient with colonic carcinoma caused by a novel Sedimentibacter species: Sedimentibacter hongkongensis sp. nov.

A bacterium was isolated from the blood culture of a 91-year-old patient with colonic carcinoma. The cells were strict anaerobic, motile, Gram-negative, sporulating, straight, or slightly curved rods. The bacterium grew on agar using the BACTEC anaerobic blood culture broth or buffered charcoal yeast extract agar as pinpoint colonies after 72 h of incubation at 37 degrees C in anaerobic conditions. It did not grow on blood agar, chocolate agar, MacConkey agar, nutrient agar or broth, brain heart infusion agar or broth, Brucella agar, or cooked meat medium. It produces catalase but not cytochrome oxidase. 16S rRNA gene sequencing and phylogenetic analysis showed that it is closely related to Sedimentibacter hydroxybenzoicus and Sedimentibacter saalensis, with 10.5% and 11.9% differences between the 16S rRNA gene sequence of the bacterium and those of S. hydroxybenzoicus and S. saalensis respectively. A new species, Sedimentibacter hongkongenesis sp. nov., is proposed, for which HKU2(T) is the type strain.