Molecular identification of Brucella bacteria in clinical samples of Sistan region by multiplex polymerase chain reaction

Brucellosis or malt fever (Mediterranean fever) occurs due to the growth and multiplication of the gram-negative coccobacillus Brucella in mammalian cells, and this disease is important as a common disease between humans and animals. Several serological tests have been investigated to identify this bacterium, however, these methods have limitations in the accurate identification of the bacterium. The present study was conducted with the aim of investigating and molecular identification of Brucella bacteria in samples collected from infected sheep in Sistan region using multiplex PCR technique. At first, blood and milk samples were collected from infected sheep. Confirmation of bacterial infection was initially done using blood samples and Rose Bengal serology method. Next, DNA was extracted from the collected milk and molecular analysis was performed using multiplex PCR and amplification of Omp31 and BLS genes, in order to amplify fragments with sizes of 347 bp and 256 bp respectively. Out of the 40 clinical samples, all of them showed a positive Rose Bengal test, but molecular analysis using multiplex PCR showed 5 false positive samples confirmed with the Rose Bengal test. Due to the higher sensitivity and accuracy and short time of identification the molecular methods can be used as a suitable option for identifying pathogens.