Application of polymerase chain reaction fingerprinting to differentiate Ornithobacterium rhinotracheale isolates

Ornithobacterium rhinotracheale (ORT) is an infectious respiratory pathogen of chickens, turkeys, and wild birds. There are 18 serotypes of ORT reported worldwide. In this study, enterobacterial repetitive intergenic consensus (ERIC) polymerase chain reaction and random amplified polymorphic DNA assay with Universal M13 primer-based fingerprinting techniques were investigated for their ability to differentiate ORT isolates. The authors examined 50 field isolates and 8 reference strains of ORT for their genetic differences. The fingerprint patterns were compared with serotyping results of ORT by the agar gel precipitation test. M13 fingerprinting revealed different patterns for 6 reference serotypes of ORT that were tested, namely, C, D, E, I, J, and K. Ornithobacterium rhinotracheale reference serotypes A and F yielded indistinguishable fingerprints with M13 fingerprinting. The ERIC 1R technique discerned only 5 of the 8 reference serotypes of ORT. Distinct fingerprints were also found within the ORT serotypes with both techniques. From 58 isolates of ORT that were fingerprinted belonging to 8 ORT serotypes, 10 different fingerprints were obtained with M13 fingerprinting and 6 different fingerprints were obtained with ERIC 1R fingerprinting. M13 fingerprinting technique was found to be more discriminative in differentiating ORT isolates than the ERIC 1R fingerprinting technique. These results suggest that fingerprinting techniques may be a more discerning tool for characterizing ORT isolates than the serological test using the agar gel precipitation test. This fingerprinting technique could potentially be a valuable tool in identifying an isolate from a clinical outbreak of ORT infection for development of an autogenous vaccine.