Genotyping Brucella canis isolates using a highly discriminatory multilocus variable-number tandem-repeat analysis (MLVA) assay

Sci Rep. 2017 Apr 21;7(1):1067. doi: 10.1038/s41598-017-01114-7.

Abstract

Differentiation of Brucella canis from other Brucella species are mainly performed through PCR-based methods and multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) procedures. Both PCR-based and MLVA methods are limited in discriminating B. canis strains. A new MLVA-13Bc method for B. canis genotyping was established by combining eight newly-developed VNTRs with five published ones. During 2010 and 2016, 377 B. canis PCR-positives were identified from 6,844 canine blood samples from 22 U.S. states, resulting in 229 B. canis isolates. The MLVA-13Bc method was able to differentiate each of these 229 isolates. The Hunter-Gaston Discriminatory Index of the individual VNTR loci ranged from 0.516 to 0.934 and the combined discriminatory index reached 1.000. Three major clusters (A, B and C) and 10 genotype groups were identified from the 229 B. canis isolates. Cluster A mainly contains genotype groups 1 and 2, and a few group 3 isolates; nearly all Cluster B isolates were from group 6; other genotype groups were classified into Cluster C. Our newly developed MLVA-13Bc assay is a highly discriminatory assay for B. canis genotyping, and can serve as a useful molecular epidemiological tool, especially for tracing the source of contamination in an event of a B. canis outbreak.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brucella canis / classification*
  • Brucella canis / genetics
  • Brucellosis / microbiology
  • Brucellosis / veterinary*
  • Cluster Analysis
  • Dog Diseases / microbiology*
  • Dogs
  • Genotype*
  • Genotyping Techniques / methods*
  • Minisatellite Repeats*
  • Molecular Typing / methods*
  • United States