Bartonella apis sp nov., a honey bee gut symbiont of the class Alphaproteobacteria

Here, we report the culture and characterization of an alphaproteobacterium of the order Rhizobiales, isolated from the gut of the honey bee Apis mellifera. Strain PEB0122(T) shares >95 % 16S rRNA gene sequence similarity with species of the genus Bartonella, a group of mammalian pathogens transmitted by bloodsucking arthropods. Phylogenetic analyses showed that PEB0122(T) and related strains from the honey bee gut form a sister Glade of the genus Bartonella. Optimal growth of strain PEB0122(T) was obtained on solid media supplemented with defibrinated sheep blood under microaerophilic conditions at 35-37 degrees C, which is consistent with the cultural characteristics of other species of the genus Bartonella. Reduced growth of strain PEB0122(T) alsd occurred under aerobic conditions. The rod-shaped cells of strain PEB0122(T) had a mean length of 1.2-1.8 mu m and revealed hairy surface structures. Strain PEB0122(T) was positive for catalase, cytochrome c oxidase, urease and nitrate reductase. The fatty acid composition was comparable to those of other species of the genus Bartonella, with palmitic acid (C-16 : 0) and isomers of 18- and 19-carbon chains being the most abundant. The genomic DNA G + C content of PEB0122(T) was determined to be about 45.5 mol%. The high 16S rRNA gene sequence similarity with species of Bartonella and its close phylogenetic position suggest that strain PEB0122(T) represents a novel species within the genus Bartonella, for which we propose the name Bartonella apis sp. nov. The type strain is PEB0122(T) (=NCIMB 14961(T)=DSM 29779(T)).