TY - JOUR

T1 - Occurrence of major and minor pathogens in calves diagnosed with bovine respiratory disease

AU - Kudirkiene, Egle

AU - Aagaard, Anne Katrine

AU - Schmidt, Louise M.B.

AU - Pansri, Potjamas

AU - Krogh, Kenneth M.

AU - Olsen, John E.

N1 - Funding Information: This study was the research part of a GUDP project funded by Danish Ministry of Environment and Food (Research Grant 34009-16-078 ). The funder had not influence on planning of the study nor on interpretation of results. Publisher Copyright: © 2021 Elsevier B.V.

PY - 2021

Y1 - 2021

N2 - Bovine respiratory disease (BRD) is caused by a mixture of viruses and opportunistic bacteria belonging to Pasteurellaceae and Mycoplasma bovis. However, these organisms are also commonly isolated from healthy calves. This study aimed to determine whether the organisms are present in higher numbers in calves sick with acute BRD than in clinically healthy calves, and further to genetically characterize bacteria of the family Pasteurellaceae to understand whether particular types are associated with disease. Forty-six clinically healthy and 46 calves with BRD were sampled by broncheoalveolar lavage (BAL) method in 11 herds geographically spread over Denmark to determine presence and quantity of microorganisms by culture and quantitative real time qPCR. Isolates of Pasteurellaceae were tested for antibiotic resistance and were whole genome sequenced to determine genotypes. Histophilus somni was in particular positively associated with BRD, suggesting particular importance of this organism as likely aetiology of BRD. In addition, quantification of bacteria revealed that higher counts of H. somni as well as of M. haemolytica was also a good indicator of the disease. Pasteurellaceae isolates were susceptible to the commonly used antibiotics in treatment of BRD, and genotypes were shared between isolates from clinically healthy and sick calves.

AB - Bovine respiratory disease (BRD) is caused by a mixture of viruses and opportunistic bacteria belonging to Pasteurellaceae and Mycoplasma bovis. However, these organisms are also commonly isolated from healthy calves. This study aimed to determine whether the organisms are present in higher numbers in calves sick with acute BRD than in clinically healthy calves, and further to genetically characterize bacteria of the family Pasteurellaceae to understand whether particular types are associated with disease. Forty-six clinically healthy and 46 calves with BRD were sampled by broncheoalveolar lavage (BAL) method in 11 herds geographically spread over Denmark to determine presence and quantity of microorganisms by culture and quantitative real time qPCR. Isolates of Pasteurellaceae were tested for antibiotic resistance and were whole genome sequenced to determine genotypes. Histophilus somni was in particular positively associated with BRD, suggesting particular importance of this organism as likely aetiology of BRD. In addition, quantification of bacteria revealed that higher counts of H. somni as well as of M. haemolytica was also a good indicator of the disease. Pasteurellaceae isolates were susceptible to the commonly used antibiotics in treatment of BRD, and genotypes were shared between isolates from clinically healthy and sick calves.

KW - Antibiotic resistance

KW - Bovine respiratory disease

KW - Diagnostics

KW - Genomics

KW - Pasteurellaceae

KW - Viral infections

U2 - 10.1016/j.vetmic.2021.109135

DO - 10.1016/j.vetmic.2021.109135

M3 - Journal article

C2 - 34090248

AN - SCOPUS:85107317920

VL - 259

JO - Veterinary Microbiology

JF - Veterinary Microbiology

SN - 0378-1135

M1 - 109135

ER -