Bartonella tamiae sp. nov., a newly recognized pathogen isolated from three human patients from Thailand

Abstract

Three strains of a novel Bartonella species (Bartonella tamiae) were isolated from human patients from Thailand. Sequence analysis of six chromosomal regions (16S rRNA, gltA, groEL, ftsZ, rpoB, and the intergenic spacer region) and phenotypical analysis supported the similarity of the three strains and placed them within the genus Bartonella separately from previously described species.

FIG. 1.

Phylogenetic tree showing the positions of strains Th239, Th307, and Th339 among members of the genus Bartonella based on comparisons of concatenated sequences of the following six genes: the 16S rRNA gene, the citrate synthase gene gltA, the RNA polymerase beta-subunit gene rpoB, the cell division gene ftsZ, the heat shock protein genes groEL, and the 16S-to-23S rRNA ITS region sequences. The 16S rRNA gene from Afipia felis was included for outgroup comparison. Bootstrap values strongly support the position of these strains in a novel clade within the genus Bartonella; however, the values do not support separating the three strains into distinct species. Trees were constructed using a maximum likelihood-based distance algorithm and a GTR+I+G DNA substitution model using PAUP software. Numbers on branches indicate the bootstrap values derived from 500 replications. The bar indicates the number of nucleotide changes.

FIG. 2.

Ultrastructure of Bartonella tamiae (strain Th239). (A) Strain Th239 after gram-negative staining showing bundles of fibrils closer to its pole (arrows). Bar = 250 nm. (B) Ultrathin section of bacterial suspension showing typical gram-negative cell walls of Bartonella tamiae organisms. Bar = 250 nm.