Frischella perrara gen. nov., sp. nov., a gammaproteobacterium isolated from the gut of the honeybee, Apis mellifera.

The gut of the Western honeybee, Apis mellifera, is colonized by a characteristic set of bacteria. Two distinct gammaproteobacteria are consistent members of this unique microbial community, and one has recently been described in a new genus and species with the name Gilliamella apicola. Here, we present the isolation and characterization of PEB0191(T), a strain belonging to the second gammaproteobacterial species present in the honeybee gut microbiota, formerly referred to as 'Gammaproteobacterium-2'. Cells of strain PEB0191(T) were mesophilic and had a mean length of around 2 µm, and optimal growth was achieved under anaerobic conditions. Growth was not obtained under aerobic conditions and was reduced in a microaerophilic environment. Based on 16S rRNA gene sequence analysis, strain PEB0191(T) belongs to the family Orbaceae, and its closest relatives, with around 95 % sequence similarity, are species of the genera Orbus and Gilliamella. Phylogenetic analyses suggest that PEB0191(T) is more closely related to the genus Orbus than to the genus Gilliamella. In accordance with its evolutionary relationship, further similarities between strain PEB0191(T) and other members of the family Orbaceae were revealed based on the respiratory quinone type (ubiquinone 8), the fatty acid profile and the DNA G+C content. Interestingly, like strains of the genus Gilliamella, PEB0191(T) exhibited a high level of resistance to oxytetracycline. The similar levels of sequence divergence from the genera Gilliamella and Orbus and its uncertain phylogenetic position within the family Orbaceae indicate that strain PEB0191(T) represents a novel species of a new genus, with the proposed name Frischella perrara gen. nov., sp. nov. The type strain of Frischella perrara is PEB0191(T) ( = NCIMB 14821(T) = ATCC BAA-2450(T)).