| Ehrlichia canis is a globally distributed agent of Canine Monocytic Ehrlichiosis. A new strain of Ehrlichia was recently detected in bovines from Brazil. According to the 16S rRNA gene, this new strain denominated Ehrlichia sp. UFMT-BV is 100% identical to the recently detected strain in Rhipicephalus microplus ticks in Brazil and dairy cattle in Canada. In addition, molecular characterization of 16S rRNA gene and immunoreactive proteins of dispersed E. canis isolates provides little information regarding the overall diversity. However, differences in the TRP36 gene of different species of Ehrlichia have been reported suggesting that TRP36 is useful for genotyping. In this investigation, we evaluate the deduced amino acid sequences of the TRP36 gene in Brazilian E. canis isolates and the new strain of Ehrlichia detected in cattle. The genomic DNA of E. canis isolates from Cuiabá/MT (Cba#1 and Cba#16), Monte Negro/RO (Mn#15 and Mn#24), Belem/PA (Bl#6), Londrina/PR (Ld), Petrolina/PE (Ptn), Pres. Prudente/SP (Ppte) and the strain UFMT-BV of Ehrlichia were obtained from cell culture and evaluated by PCR using universal primers TRP36-F2 (5’-TTTAAAACAAAATTAACACACTA-3’) and TRP36-R1 (5’-AAGATTAACTTAATACTCAATATTACT-3’) in order to obtain full TRP36 gene sequences. The isolates of E. canis Cba#16, Ppte and Ptn had an deduced amino acid Tandem Repeat (TR) sequence `TEDSVSAPA` identical to that previously reported in America, Asia, Africa and Europe. These strains were classified as US genotypes. Notably, a new Brazilian genogroup that had the TR sequence `ASVVPEAE` was represented by isolates Cba#1, Mn#15, Mn#24, Bl and Ld. Analysis of the TRP36 gene of Ehrlichia sp. UFMT-BV revealed substantial diversity between these Ehrlichia genotypes strains, including a novel TR sequence `VSADSGAAQ`. We concluded that different E. canis and others genotypes of Ehrlichia can be molecularly distinguished by the TRP36 gene, which can be widely utilized to define Ehrlichia strain diversity. |
