Rapid detection of Ornithobacterium rhinotracheale in commercial poultry farms of Andhra Pradesh by SYBR Green Real-Time PCR

The present work was carried out to isolate and identify one of the important respiratory pathogens Ornithobacterium rhinotracheale and to study the incidence of ORT in commercial poultry farms in various districts of Andhra Pradesh. An attempt was made to rapidly detect ORT in poultry with respiratory infections. A total of 28 farms altogether, samples collected include 113 tracheal swabs, 79 nasal swabs, 104 oral swabs, 91 exudates of infraorbital sinuses, 52 heart blood swabs, 63 tracheal tissues, 63 liver tissues, 63 lung tissues, and 34 air sacs from 28 farms located in various districts of Andhra Pradesh. On conventional isolation 20 farms farms were to be positive. Then the isolates were allowed for DNA extraction by lysis (boiling) method. From all the field samples, reference samples were screened by SYBR Green Real-Time PCR which were positive in conventional PCR. The screened samples were also positive for SYBR Green Real-Time PCR. The Ct values ranged from 12-24 for the 16S r RNA gene and 15-30 for the rpoB gene. The optimal cut-off Ct values for ORT in Real-Time PCR is found to be 9.39 to 32.97.