Genomic characterization of Mycoplasma bovis, Mannheimia haemolytica, and bovine viral diarrhea virus 1 from a bovine respiratory disease complex case
摘要
Bovine respiratory disease (BRD) complex is a result of the interactions among pathogens, environmental factors, host factors, and management practices. Bacterial pathogens that contribute to BRD include Mycoplasma (Mycoplasmopsis) bovis, Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni. Viral agents that contribute to BRD include bovine herpesvirus 1, bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus, parainfluenza-3 virus, bovine coronavirus, and influenza D virus.
ResultsA case of BRD was submitted to the California Animal Health and Food Safety Laboratory for diagnostic evaluation. Bacterial and viral pathogens were isolated from a pneumonic lung sample including M. bovis, M. haemolytica, and BVDV. The DNAs/RNA of the pathogens were extracted, sequenced, analyzed, and compared to publicly available sequencing data. The genome of M. bovis was identified as a unique sequence type (ST299) with two novel alleles (gltX 28 and gpsA 32) and contained unique variable surface lipoproteins. However, the M. bovis genome also phylogenetically clustered with the M. bovis type strain PG45. The genome of M. haemolytica was similar to other publicly available M. haemolytica genomes, as it was assigned to sequence type 1 (ST1) and serotype 1. Finally, the genome of the isolated BVDV strain showed high similarity to the Singer (BVDV-1a) vaccine strain.
ConclusionAs BRD is a complex, case studies in which the pathogens co-occur in the lung are important to report. Here, we report the complete genomes of three pathogens isolated from a single pneumonic lung sample. Notably, the M. bovis genome represents a unique sequence type. Future work should investigate the influence of the nine amino acid changes between the UCD-16 BVDV isolate and the Singer strain on disease pathogenesis.