Molecular Identification of Hemoplasmas in Dogs Exposed to Ticks: A Retrospective Study

Canine hemotropic mycoplasmosis (hemoplasmosis) is a disease associated with anemia that has been reported in dogs with a widespread geographical distribution. The etiologic agent is an epierythrocytic bacteria that is located in the erythrocytes` surface of the affected host. There is a lack of information on hemoplasma infections in dogs in Mexico and particularly on the use of molecular methods for the detection of this microorganism. This study aimed to perform PCR assays and sequence analysis to investigate dogs and ticks for the presence of canine hemoplasma species.The objective of this study was to identify the presence of canine hemoplasmas in archived blood samples collected from 30 dogs and ticks collected from 18 of those dogs. The samples were processed for DNA extraction and amplification by PCR with 16S rRNA gene primers for Mycoplasma spp. Out of the samples analyzed, the PCR assay allowed the identification of DNA amplicons of the expected size in 20 and 4 of the blood and tick samples, respectively. Sequence analysis using the local alignment bioinformatics tool (BLASTn) of 8 sequenced samples showed highly significant identity percentages compatible with the presence of various hemoplasma species in the sequenced samples: Mycoplasma haemocanis (2 samples), Candidatus Mycoplasma haematoparvum (2 samples), Mycoplasma wenyonii (2 samples), Mycoplasma ovis (1 sample), and a nonculturable bacterium (1 sample). It is suggested to carry out a more in-depth analysis through the amplification and sequencing of other structural genes present in the Mycoplasma spp genome, to confirm whether all the identified hemoplasma species can effectively infect the dog, or the amplified region of the 16S rRNA gene is not sufficiently variable among the different hemoplasmas that affect domestic animals to allow discrimination of these Mycoplasma species.