BepE is essential for Bartonella tribocorum (Btr) to establish bacteremia after intradermal (i.d.) infection of the rat reservoir host.

(A) Domain organization of BepE orthologues in Btr and Bhe. The BepE homologues from Bartonella species depicted in the figure (BepE_Bhe, BepD_Btr, BepE_Btr) were aligned using Geneious Pro 5.3.4. The amino acid sequence alignment with pairwise % identity is indicated. The tyrosine-containing N-termini and BID domains were aligned independently. (B) Btr ΔbepDE is not able to reach the blood of rats infected by the i.d. route. Rats (n = 5) were inoculated in the ear dermis with either Btr wild-type or Btr ΔbepDE. Blood was drawn at the indicated days post infection (dpi), diluted and plated on sheep blood supplemented Columbia agar plates (CBA) for counting of colony forming units (CFUs). (C) Complementation of the Btr ΔbepDE mutant with BepE is sufficient to restore bacteremia in rats infected by the i.d. route. Groups of rats (n≥3) were infected with the indicated strains by the i.v. or i.d. route. Blood was drawn at 16 dpi and CFUs were recovered as described for B. The graph represents CFUs/ml of blood for individual animals (circles) and their cohort mean (line). Statistical significance was determined using Student's t-test. P<0.05 was considered statistically significant. (D) Heterologous complementation of Btr ΔbepDE with pBIDs.E_Bhe is sufficient to rescue the abacteremia phenotype following infection by the i.d. route. The infections were performed as described for (C). Data represented for BIDs.E_Bhe complementation were acquired in separate experiment from the other data shown. P<0.05 was considered statistically significant.