Experimental evidence of host specificity of Bartonella infection in rodents

A large number of Bartonella species and genetic variants were compared for their ability to cause bacteremia in different rodent species: the cotton rat (Sigmodon hispidus), white-footed mouse (Peromyscus leucopus), BALB/c m ouse and Wistar rat. Experimental data supported field observations that ho st specificity can occur among certain Bartonella species and rodent specie s. Bacteremia could only be readily produced in cotton rats or white-footed mice if the strains used for inoculation were originally obtained from the same species or from a phylogenetically close species. A few Bartonella co lonies could be observed in the blood of some BALB/c mice by 7 days after i noculation, but no evidence of the persistence of the infection was found. Host specificity suggests the possibility of a long co-speciation of Barton ella species with their rodent hosts. Host-parasite relationships measured by the duration and level of bacteremia and the minimal infectious dose may serve as additional criteria for classification of Bartonella isolates obt ained from natural environments. Published by Elsevier Science Ltd.