Frischella japonica sp. nov., an anaerobic member of the Orbales in the Gammaproteobacteria, isolated from the gut of the eastern honey bee, Apis cerana japonica Fabricius

The gut of honey bees is characterized by a stable and relatively simple community of bacteria, consisting of seven to ten phylotypes. Two closely related honey bees, Apis mellifera (western honey bee) and Apis cerana (eastern honey bee), show a largely comparable occurrence of those phylotypes, but a distinct set of bacterial species and strains within each bee species. Here, we describe the isolation and characterization of Ac13(T), a new species within the rare proteobacterial genus Frischella from A. cerana japonica Fabricius. Description of Ac13(T) as a new species is supported by low identity of the 16S rRNA gene sequence (97.2 %), of the average nucleotide identity based on orthologous genes (77.5 %) and digital DNA–DNA hybridization relatedness (24.7 %) to the next but far related type strain Frischella perrara PEB0191(T), isolated from A. mellifera. Cells of Ac13(T) are mesophilic and have a mean length of 2–4 µm and a width of 0.5 µm. Optimal growth was achieved in anoxic conditions, whereas growth was not observed in oxic conditions and strongly reduced in microaerophilic environment. Strain Ac13(T) shares several features with other members of the Orbaceae, such as the major fatty acid profile, the respiratory quinone type and relatively low DNA G+C content, in accordance with its evolutionary relationship. Unlike F. perrara, strain Ac13(T) is susceptible to a broad range of antibiotics, which could be indicative for an antibiotic-free A. cerana bee keeping. In conclusion, we propose strain Ac13(T) as a novel species for which we propose the name Frischella japonica sp. nov. with the type strain Ac13(T) (=NCIMB 15259=JCM 34075).