Comparison of culture and PCR for the detection of Brucella melitensis in blood and lymphoid tissues of serologically positive and negative slaughtered sheep

Lett Appl Microbiol. 2008 Mar;46(3):301-6. doi: 10.1111/j.1472-765X.2007.02309.x. Epub 2007 Dec 20.

Abstract

Aims: To compare the culture and PCR methods for detection of Brucella melitensis in blood and lymphoid tissue samples obtained from slaughtered sheep (n = 162) testing positive/negative in serological tests (Rose Bengal test and serum agglutination test).

Methods and results: Of 162 sheep examined, 45 were positive and 117 negative in serological tests. A PCR assay based on a pair of Br. melitensis-specific primers was used to detect DNA in blood and lymphoid tissue. Brucella melitensis was isolated from 1.2% (2/162) and 17.2% (28/162) of the blood and lymphoid tissue samples respectively. Positive PCR products with a molecular size of 731 bp were obtained from 27.7% (45/162) of blood and 29.0% (47/162) of lymphoid tissue samples.

Conclusions: The species-specific PCR assay detected a higher number of Br. melitensis DNA both from serologically positive (P < 0.01 in blood PCR, P < 0.001 in tissue PCR) and serologically negative (P < 0.001 in both blood PCR and tissue PCR) sheep compared with classical bacteriological culture methods.

Significance and impact of the study: The results emphasize the importance of using more than one type of diagnostic technique for the detection of animals positive for brucellosis, especially with epidemiological purposes.

Publication types

  • Comparative Study
  • Evaluation Study

MeSH terms

  • Abattoirs
  • Animals
  • Antibodies, Bacterial / blood
  • Bacteriological Techniques
  • Blood / microbiology*
  • Brucella melitensis / genetics
  • Brucella melitensis / immunology
  • Brucella melitensis / isolation & purification*
  • Brucellosis / immunology
  • Brucellosis / microbiology
  • Brucellosis / veterinary
  • Culture Media*
  • DNA, Bacterial / analysis
  • DNA, Bacterial / isolation & purification
  • Female
  • Lymphoid Tissue / microbiology*
  • Mammary Glands, Animal / microbiology
  • Polymerase Chain Reaction / methods*
  • Sensitivity and Specificity
  • Sheep Diseases / immunology
  • Sheep Diseases / microbiology*
  • Species Specificity

Substances

  • Antibodies, Bacterial
  • Culture Media
  • DNA, Bacterial