Abstract: To establish a duplex PCR method for simultaneously detecting Brucella and Chlamydia psittaci, this study obtained two genus-specific gene sequences according to the GenBank, including bp26 of Brucella spp. and 23S rRNA of Chlamydia psittaci. Two pairs of specific primers were respectively designed. After optimizing the reaction condition, the duplex method was established for simultaneously detecting Brucella and Chlamydia psittaci. The method had better specificity and repeatability, the detection sensitivity of simplex method for each gene both could reach 3.1×10² copies per reaction, the detection sensitivity of duplex method for each gene could reach 3.1×10³ copies per reaction. Using this duplex method to detect 172 samples including bloods, sera, placentas of abortion cattle and milk suspected infecting Brucella in clinic,53 Brucella positive samples and 2 Chlamydia psittaci positive samples were detected out, the positive rates were 30.8% and 1.2%, separately. 2 co-infection positive samples were detected out else and the positive rate was 1.2%. The above results indicated that this method could be used for simultaneously, rapidly and sensibly detecting the two pathogens of Brucella and Chlamydia psittaci.

Key words: Brucella; Chlamydia psittaci; duplex PCR; co-amplification