Equine and canine Anaplasma phagocytophilum strains isolated on the island of Sardinia (Italy) are phylogenetically related to pathogenic strains from the United States

Abstract

The presence of Anaplasma phagocytophilum, a tick-transmitted zoonotic pathogen, was investigated in Sardinia using a molecular approach. Phylogenetic analysis revealed that Sardinian strains are genetically distinct from the two lineages previously described in Europe and are closely related to strains isolated in different areas of the United States.

FIG. 1.

Results of groEL PCRs and HindIII digestion. Lane MW contained molecular weight standards. Lane 1 contained amplicon obtained after the first PCR round starting with DNA extracted from the buffy coat of a symptomatic dog. Lanes 2, 4, 6, and 8 show groEL heminested PCR results obtained using internal primer EPhGroR, specific for A. phagocytophilum, with DNA extracted from the reference strain of A. phagocytophilum and from samples Stechi, Sogno, and Perla, respectively. To the right of each PCR result, the corresponding HindIII digestion result is shown (lanes 3, 5, 7, and 9). Lanes 10 and 12 show groEL heminested PCR results obtained using internal primer EPlGroR, specific for A. platys, with DNA extracted from the control strain of A. platys and from sample Lara, respectively. To the right of each PCR result, the corresponding HindIII digestion result is shown (lanes 11 and 13). Lane 14 shows HindIII digestion of the amplicon obtained after the first PCR (lane 1) and identification of the sample as A. platys.

FIG. 2.

Coinciding NJ and MP trees generated by considering 39 A. phagocytophilum sequence types OTUs for phylogenetic analyses. The numbers in parentheses are statistically significant bootstrap values for the branches obtained by testing the robustness of NJ trees. The numbers not in parentheses are statistically significant consensus values for branches obtained by testing MP trees.