Comparison of a Serological Method, a Bacteriological Method and 16S rRNA Brucella canis PCR for Canine Brucellosis Diagnosis

The objective of the study was to evaluate the sensitivity, specificity and the positive and negative predictive value of a PCR assay for canine brucellosis diagnosis using 16S rRNA specific primers compared to serology, 2 mercaptoethanol-microtiter plate agglutination tests (2ME-MPAT) and a blood culture test. A sample of 48 dogs was divided into three groups, according to the results of blood culture tests and 2ME-MPAT. Group 1was comprised of infected Brucella canis dogs, who were positive to both a blood culture test and 2ME-MPAT (n=16). Group 2 contained non-infected B. canis dogs, who were negative to both a blood culture test and 2ME-MPAT (n=16). Group 3 contained suspected infected B. canis dogs, who were negative to a blood culture test but positive to 2ME-MPAT (n=16). Samples in Groups 1 and 2 were used to calculate the diagnostic sensitivity, specificity, positive predictive value and negative predictive value of PCR and the results performed in Group 3 were also discussed. The diagnostic sensitivities and specificities of PCR were 100%. The positive and negative predictive values and accuracy of PCR were 100%. In conclusion, the results revealed that the PCR was an effective technique for the diagnosis of canine brucellosis in blood samples, especially in dogs suspected of being positive by 2ME-MPAT, but negative by a blood culture test.