Submitted to: Journal of Clinical Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/12/2010
Publication Date: 4/1/2010
Citation: Gopaul, K.K., Sells, J., Bricker, B.J., Crasta, O.R., Whatmore, A.M. 2010. Rapid and Reliable Single Nucleotide Polymorphism-Based Differentiation of Brucella Live Vaccine Strains from Field Strains. Journal of Clinical Microbiology. 48(4):1461-1464. Interpretive Summary: Brucellosis, also known as Bang’s Disease or Undulant Fever, is a serious disease of livestock animals, and sometimes humans, throughout the world. The best way to control the disease is by vaccination of animals with special live bacteria selected for the local types of animals and disease. There are three vaccines predominantly used world wide. Sometimes, when animals are tested for the disease it can be hard to know if the animal is reacting to a disease bacterial strain or to the vaccine strain. Also, over the many decades that these vaccines have been used, some countries or regions vaccinate animals with variations of the vaccine strains that are different in the characteristics typically used to identify them as vaccines. In this paper, new characteristics were selected to identify the vaccine strains from the disease strains. These new characteristics are based on tiny changes in the vaccine bacteria’s DNA. These changes were found to be sustained in the respective vaccines from different locations, and even in the vaccine variants which no longer have some of the traditional vaccine characteristics. Based on these new “marker” characteristics, new diagnostic tests were developed that are fast and reliable.
Technical Abstract: Brucellosis is a major zoonotic disease responsible for substantial social and economic problems, particularly in the developing world. One element that can implemented as part of control programs tackling animal disease is the use of one of the OIE recommended vaccines to protect against either Brucella melitensis (Rev1 vaccine) or Brucella abortus (S19 or RB51 vaccines). As all recommended vaccines against brucellosis are live it is important to be able to distinguish vaccine strains from wild type isolates. We present here a novel use of real-time PCR to identify the vaccine strains based on Single Nucleotide Polymorphisms (SNPs). Furthermore we show how combining these assays with a tool identifying isolates to the species level described previously provides a useful and more comprehensive tool for molecular typing of Brucella.