Gram-negative bacteria associated with brewery yeasts: reclassification of Obesumbacterium proteus biogroup 2 as Shimwellia pseudoproteus gen. nov., sp. nov., and transfer of Escherichia blattae to Shimwellia blattae comb. nov.

Phylogenetic analyses of type and reference strains of Obesumbacterium proteus biogroups 1 and 2 plus a novel isolate of biogroup 2 were carried out based on 16S rRNA gene sequences and partial sequences of four protein-coding genes (fusA, leuS, pyrG and rpoB). Both approaches revealed that O. proteus biogroup 1 strains were closely related to Hafnia alvei. Biogroup 2 strains, however, formed a distinct monophyletic clade of generic status that included Escherichia blattae. Phenotypic tests were consistent with the molecular classification and provided diagnostic features. It is proposed that biogroup 2 strains be placed in a new genus, Shimwellia gen. nov., as Shimwellia pseudoproteus sp. nov., with strain 521(T) (=DSM 3038(T)=LMG 24835(T)=NCIMB 14534(T)) as the type strain, and that Escherichia blattae be transferred to the genus Shimwellia as Shimwellia blattae comb. nov., with strain ATCC 29907( T) (=DSM 4481(T)) as the type strain.