Polyphasic taxonomic approach in the description of Alishewanella fetalis gen. nov., sp. nov., isolated from a human foetus.

A taxonomically unique bacterium is described on the basis of a physiological and biochemical characterization, fatty acid profiling and sequence analyses of 16S rRNA and gyrase B (gyrB) genes. This non-motile, non-fermentative bacterium was isolated from a human foetus in Uppsala, Sweden, and originally misidentified as a Shewanella putrefaciens by conventional biochemical testing. The bacterium grew well at mesophilic temperatures with optimum growth at 37 degrees C. It was facultatively anaerobic and utilized various electron acceptors (trimethylamine oxide, nitrate, nitrite and thiosulphate). The dominant fatty acids were 17:1B, 16:1 cis9, 17:0 and 16:0. Fatty acids 13:0 iso and 15:0 iso, which have been found to be typical of Shewanella species were not detected. The G+C content of the DNA was 50.6 mol%. Phylogenetic analysis of the 16S rRNA gene sequence revealed a clear affiliation with members of the gamma subclass of the Proteobacteria. No relationship was seen with any of the established genera in the gamma subclass of the Proteobacteria, although a distinct relationship with Vibrionaceae was observed. That the bacterium represents a novel bacterial genus distinct from Vibrionaceae was also supported by gyrB sequence analysis. Considering the source and close proximity to the genus Shewanella, the name Alishewanella fetalis gen. nov., sp. nov. is proposed, for which the type strain is strain CCUG 30811T.