Detection of Coxiella burnetii and sequencing the IS1111 gene fragment in bulk tank milk of dairy herds

Coxiella burnetii is the etiologic agent of Q fever in human. This study is aimed to determine the contamination rate of C. burnetii in bulk tank milk samples. In this study, a total number of 100 bulk milk samples collected from dairy farms in northeast of Iran and were examined for C. burnetii using touchdown PCR assay. The primers were designed to amplify a 687-bp fragment of the IS1111 gene of C. burnetii. Five samples (5%) of bovine milk were found positive for C. burnetii. Sequence analysis of PCR products revealed 100% identity with published sequences of C. burnetii in genBank. Results of this study indicate that bovine milk is an important source of C. burnetii infection in Iran.