Serological and Nucleic Acid Based Detection of Brucellosis in Livestock Species and Molecular Characterization of Brucella melitensis Strains Isolated from Pakistan

This study aimed at molecular detection and characterization of Brucella spp from Pakistan. For this purpose, whole blood samples (n= 167) were collected from different species of livestock and analysed at Animal and Plant Health Agency (APHA), United Kingdom. Samples were analysed employing Rose Bengal Test (RBT), Competitive Enzyme-linked immunosorbent assay (cELISA), PCR IS711 and culture examination. We found 1% (2/167) samples positive for infection by culture, 4% (7/167) by RBT, 6% (10/167) by cELISA and 21% (35/167) by PCR IS711. Results were found statistically significant using chi-square test (p-value < 0.05). The blood culture positive bacterial isolations were further subjected to classical biotyping and molecular techniques for characterization and found as non-vaccine strains of Brucella melitensis. Molecular characterization using Multilocus Sequence Analysis (MLSA) and Variable Number of Tandem Repeat (VNTR) analysis demonstrated that although there was some similarity in the patterns generated, the isolations were distinct from each other. These isolates were not the part of geographically confined group but were representative of other B. melitensis strains found in the region stretching from southern Europe into South Asia. To our knowledge, this is the first report of molecular characterization of B. melitensis isolates from Pakistan. The molecular methods described in the present study will help to understand the disease dynamics and future brucellosis control in Pakistan. (C) 2016 Friends Science Publishers