| Autor: |
Kinnear A; Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada., McAllister TA; Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB T1J 4B1, Canada., Zaheer R; Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB T1J 4B1, Canada., Waldner M; Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada., Ruzzini AC; Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada.; College of Medicine, Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada., Andrés-Lasheras S; Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB T1J 4B1, Canada., Parker S; Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada., Hill JE; Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada., Jelinski MD; Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada. |
| Abstrakt: |
Mycoplasma bovis is associated with bovine respiratory disease (BRD) and chronic pneumonia and polyarthritis syndrome (CPPS) in feedlot cattle. No efficacious vaccines for M. bovis exist; hence, macrolides are commonly used to control mycoplasmosis. Whole genome sequences of 126 M. bovis isolates, derived from 96 feedlot cattle over 12 production years, were determined. Antimicrobial susceptibility testing (AST) of five macrolides (gamithromycin, tildipirosin, tilmicosin, tulathromycin, tylosin) was conducted using a microbroth dilution method. The AST phenotypes were compared to the genotypes generated for 23S rRNA and the L4 and L22 ribosomal proteins. Mutations in domains II (nucleotide 748; E. coli numbering) and V (nucleotide 2059 and 2060) of the 23S rRNA ( rrl ) gene alleles were associated with resistance. All isolates with a single mutation at Δ748 were susceptible to tulathromycin, but resistant to tilmicosin and tildipirosin. Isolates with mutations in both domain II and V (Δ748Δ2059 or Δ748Δ2060) were resistant to all five macrolides. However, >99% of isolates were resistant to tildipirosin and tilmicosin, regardless of the number and positions of the mutations. Isolates with a Δ748 mutation in the 23S rRNA gene and mutations in L4 and L22 were resistant to all macrolides except for tulathromycin. |
