Respiratory infection is one of the most common problems facing the livestock industry in Egypt, and results in substantial economic losses.
Aim: The current study investigated the prevalence and molecular characterization of common bacterial pathogens associated with respiratory symptoms in young calves from Sadat City, Menoufiya Governorate, Egypt.
Material and methods: In between December 2020 and March 2021, 200 mixed-breed young calves of 6–12 months were examined clinically. Deep nasal (Nasopharyngeal) swabs were collected from sixty (30%) calves showed signs of respiratory manifestations, for bacteriological investigation. The identity of the isolated bacteria was confirmed by PCR. Then partial gene sequencing was done on the isolated bacterial species.
Results: Phenotypic characterization and identification revealed Mycoplasma bovis, Mycoplasma bovigenitalium, Pasteurella multocida, and Staphylococcus aureus in 8.33%, 5%, 5%, and 5% of the tested samples, respectively. PCR confirmed the identity of the isolated bacteria. The low prevalence of these pathogens compared to other studies carried out in Egypt has been implicated to the low number of samples or application of vaccination programs in the study area. Partial gene sequencing of 16S rRNA gene of M. bovigenitalium, P. multocida, and S. aureus, and mb-mp 81 gene of M. bovis revealed high nucleotide similarity and genetic relationship with respective bacterial species reported from Egypt and around the world.
Conclusion: the high identity and similarities of isolates within several global and local linages suggests the possible spread of these bacterial pathogens across animal species and different geographic locations. Further studies using whole genome sequencing (WGS) and large number of isolates are required to investigate the realistic lineage of Egyptian isolates and globally.