Brucella abortus detection by PCR assay in blood, milk and lymph tissue of serologically positive cows.
Brucellosis is a highly infectious disease which is diagnosed using serological and microbiological methods. The objective of this study was to assess the viability of using conventional and real-time PCR assays as potential diagnostic tools for the detection of Brucella abortus in naturally infected cows. PCR assays that amplify various regions of the Brucella genome, IS711 genetic element, 31kDa outer membrane protein and 16S rRNA, were optimised using nine known Brucella strains. Real-time PCR was used to examine the detection efficiency of the IS711 assay which was estimated at 10 gene copies. Milk, blood and lymph tissue samples were collected from naturally infected animals. B. abortus was not detected in blood samples collected from naturally infected cows by conventional or real-time PCR, but was detected in a proportion of the culture-positive milk (44%) and lymph tissue (66% - retropharyngeal, 75% - supramammary) samples by the same methods. There was no difference between PCR and bacteriological detection methods. It is unlikely that conventional or real-time PCR will supersede current diagnostic methods for detection of B. abortus in clinical samples.
Department of Animal Husbandry and Production, Faculty of Veterinary Medicine and The Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.
Seónadh
S
O'Leary
Michael
M
Sheahan
Torres
T
Sweeney
D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics; D002003:Brucella abortus / Q000235:genetics / Q000302:isolation & purification*; D002007:Brucellosis, Bovine / Q000097:blood / Q000382:microbiology*; D002417:Cattle; D015169:Colony Count, Microbial / Q000662:veterinary; D004251:DNA Transposable Elements / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005260:Female; D008198:Lymph Nodes / Q000382:microbiology*; D008892:Milk / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012336:RNA, Ribosomal, 16S / Q000737:chemistry / Q000235:genetics
D001425:Bacterial Outer Membrane Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S