Proteus faecis sp. nov., and Proteus cibi sp. nov., two new species isolated from food and clinical samples in China

Eight swarming motile bacteria were isolated from food and clinical samples in China. Cells were Gram-stain-negative, facultatively anaerobic and rod-shaped (0.5-0.8x 1.0-3.0 mu m) with hairlike pili and flagella. The 16S rRNA and partial rpoB housekeeping gene sequence analyses indicated that the strains belong to the genus Proteusin the family Enterobacteriaceae. Of the eight strains studied, seven and a single isolate formed two separate clades in the phylogeny of Proteusspecies, indicating two separate species. Both the in silico DNA-DNA hybridization and the average nucleotide identity values between these two groups and to the type strains of the genus Proteuswere below the recommended threshold for signifying their candidature as two separate species. The DNA G+C contents of strains TJ1636(T)and FJ2001126-3(T) were 37.8 and 38.1 mol%, respectively. The major cellular fatty acids of the two novel type strains were C(16:0, )cyclo C-17:0, summed feature 3 and summed feature 8. The results supported that the strains belong to different taxonomic positions in the genus Proteus. The isolates were named Proteus faecis sp. nov., with type strain TJ1636(T) (=DSM 106180(T) =GDMCC 1.1245(T)), and Proteuscibi sp. nov., with type strain FJ2001126-3(T )(=DSM 106178(T) =GDMCC 1.1244(T)).