Amplified 16S ribosomal DNA restriction analysis for identification of Avibacterium paragallinarum

A molecular technique based on the restriction fragment length polymorphism of the 16S ribosomal genes amplified by a polymerase chain reaction (PCR), referred to as amplified 16S ribosomal DNA restriction analysis (ARDRA), was designed to identify 19 Avibacterium paragallinarum strains isolated from infraorbital sinus and nasal turbinate bone samples of broiler chickens, breeders, and laying hens from different regions of Peru. The 16S rDNA was amplified by PCR using a pair of bacterial universal primers and restriction analysis of 16S rDNA sequences was done to select endonucleases with the highest number of cutting points inside the 16S rDNA. The DNA patterns with DdeI and RsaI endonucleases were identical for the 19 A. paragallinarum strains, but differed from those obtained for Ornithobacterium rhinotracheale, a bacterium with a high genetic and phenotypic resemblance to A. paragallinarum, as well as from Escherichia coli, a bacterium associated with infectious coryza. The ARDRA method could prove to be valuable for molecular identification of A. paragallinarum, a microorganism implicated in respiratory diseases in commercial birds.