Molecular Detection of The Ornithobacterium rhinotracheale From Turkeys Flocks in Alexandria Governorate During 2020 – 2021

Abstract

Ornithobacterium rhinotracheale (ORT) bacterium in poultry causes respiratory disease with reduced body weight, and lowered hatchability. The disease has higher incidence in turkey species, rapidly developing antibiotic resistance, and difficulties in its diagnosis lead to higher economic losses, drug costs, misdiagnosis. Therefore, this work aimed to follow incidence of ORT bacterium in turkeys by using Polymerase Chain Reaction (PCR) in addition to sequencing, and phylogenetic analysis. Aspirated infected nasal fluids of seventeen turkey flocks affected with sinusitis were tested using PCR method for 16S rRNA genes of ORT then seven isolates were selected for sequencing, and phylogenetic analysis, followed by Gene Bank database submission. PCR results were positive for ORT bacterium at amplicon of 625 bp fragment in 12 out of 17 investigated turkey flocks with a percent of 70.59%.On sequencing of 16S rRNA genes, the selected isolates exhibited 100% similarity with each other, and Tur/France/94 strain and 99.8% with the Egyptian strains (MG773129-Egy-1, and MG773129-Egy-2), Tur/Hungary/2015, Ch/USA/91, Ch/South Africa/91, and Ch/France/95. All sequenced isolates were registered on the GenBank database and accession numbers were taken as follow, MW700375, MW700376, MW700377, MW700378, MW700379, MW700380, and MW700381. The higher incidence of ORT infection in turkey flocks was indicated that ORT alone could trigger turkey sinusitis with respiratory signs, also, their similarity of 99.8% with other Egyptian ORT strains means there were variation occurred in 16S rRNA gene which might play an important role in generation of new variant ORT strains.