Characterization of six clinical isolates of Chimaeribacter gen. nov., a novel genus related to the Yersiniaceae family and the three species Chimaeribacter arupi sp. nov., Chimaeribacter coloradensis sp. nov, and Chimaeribacter californicus sp. nov.

Eight genetically related, Gram-negative bacterial strains, isolated from clinical specimens between 2012 and 2016, were submitted to ARUP Laboratories for species identification. The lack of species- or genus-level matches in curated 16S rRNA gene databases prompted us to undertake the polyphasic characterization of these so far undescribed organisms. Six isolates available for additional testing were oxidase negative, catalase positive, pleomorphic, Gram-negative rods displaying temperature-dependent motility and producing yellow-pigmented colonies with three distinct morphotypes: medium-sized shiny, large mucoid and agar-pitting. Biochemical reactions and sugar fermentation patterns were most similar to members of the genus Serratia. Fatty acid profiles were highly similar across all six organisms, with the major components being: C-16:0, C-17:0 cyclo; C-14:0 3-OH/iso-C-16:1 l; C-18:1 omega 7c; and C-16:1 omega 7c/C-16:1, omega 6c. Whole-genome comparisons and multi locus sequence analysis (using the coding genes atpD, rpoB, gyrB and infB) suggest that the strains here described constitute three individual species within a novel genus related to the family Yersiniaceae. We propose for this novel taxon the name Chimaeribacter gen. nov., referring to the presentation of multiple characteristics typical of distinct Enterobacterales genera within a single organism. Four isolates are representative of a single species: Chimaeribacter arupi sp. nov (2016-lso1, 2016-lso2, type strain 2016-lso3(T) =DSM 110101(T)=ATCC TSD-180(T) and 2013-lso5). The remaining two isolates constitute the novel species Chimaeribacter coloradensis sp. nov. (type strain 2016-lso4(T) =DSM 110102(T)=ATCC TSD-182(T)) and Chimaeribacter californicus sp. nov. (type strain 2015-lso6(T) =DSM 110100(T) =ATCC TSD-181(T)). Our work provides the first formal characterization of the genus Chimaeribacter and forms the basis to study its taxonomic diversity.