Use of chimeric DNA-RNA primers in quantitative PCR for detection of Ehrlichia canis and Babesia canis.

To overcome the problem of nonspecific by-products in quantitative PCR (qPCR) assays, we constructed DNA-RNA chimeric primers and evaluated their use in the detection and quantification of the Ehrlichia canis 16S rRNA, Babesia canis Hsp70, and canine beta-actin genes. Several RNA bases were incorporated into specific positions in the DNA primers, while no RNA stretches were allowed. qPCR reactions were carried out without preamplification steps. This resulted in decreased formation of undesirable by-products and a 10-fold increase in assay sensitivity.