In silico analysis to develop PCR assays for identification of bacterial pathogens in animals: what can we improve?

Development and Validation of PCR Diagnostic Assays for Detection of Avibacterium paragallinarum and Ornithobacterium rhinotracheale

PCR is the most effective method for detecting difficult-to-cultivate pathogens and pathogens that are part of mixed infections in animals, such as Ornithobacterium rhinotracheale, which causes bird ornithobacteriosis, or Avibacterium paragallinarum, which causes infectious coryza. In this work, we developed and validated two efficient and sensitive diagnostic assays for the rapid and accurate detection of A. paragallinarum and O. rhinotracheale DNA in bacterial isolates and clinical samples using real-time PCR with TaqMan-like probes. When designing the PCR assays, we performed in silico analysis, optimized DNA isolation methods and PCR conditions, and assessed the analytical and diagnostic performance of PCR. We designed primers and probes that have no mismatches with published whole-genome sequences of bacteria. The optimization of conditions showed that the PCR assays are sufficiently robust to changes in temperature and oligonucleotide concentration. The validation showed that the developed assays have high analytical and diagnostic sensitivity and specificity. These assays are expected to improve the differential diagnosis of respiratory diseases in chickens and turkeys.