The phylogenetic analysis of some Ornithobacterium rhinotracheale isolates from industrial chicken flocks of Alborz province

Ornithobacterium rhinotracheale (ORT) has been identified as one of the emerging respiratory bacterial pathogens in turkey and chicken flocks. The aim of this study was the analysis of 16S ribosomal RNA nucleotide sequences of some isolates from Alborz province chicken flocks. For this purpose, 10 ORT isolated and identified by culture method from commercial chicken flocks of Alborz province were selected. After DNA extraction using phenol-chloroform method, all samples were tested by specific PCR for ORT identification. The second PCR for amplification of 16S rRNA complete gene was set-up and then about 1450-bp bands were sequenced. Multiple alignment and phylogenic analysis of DNA sequences were performed with Bioedit and MEGA programs. Phylogenetic analysis of ORT isolated from Alborz province (6 of broiler origin, 3 of layer origin and 1 of broiler breeder origin) and 63 ORT sequences obtained from Gen bank from all around the world showed high genetic similarity (98.6% - 100%) among them. The 16S rRNA sequence of 73 ORT sequences were grouped into three genetic clusters.  The Alborz isolates showed 100% similarity. These 10 isolates showed the most  homology with ORT isolated from USA, Russia and Taiwan. Overall, these results revealed the same molecular structure and high homology among ORT isolates from Alborz province.