1Department of Bacteriology, Kimron Veterinary Institute, Bet Dagan 2The Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot
Brucellosis is a worldwide zoonotic disease caused by Gram-negative bacteria of Brucella species. Brucellosis is acquired by a direct contact with infected animals, their tissues or by consumption of contaminated unpasteurized dairy products. The causative agents of the disease, Brucella spp., are facultative intracellular pathogens capable of infecting professional and nonprofessional phagocytes. In spite of the high economic, environmental, and health costs of Brucella spp., little is known about the regulation of their virulence factors. Brucella spp. are susceptible to brucellaphages, which are species specific. Since bacterial phages are known to have regulatory functions on their host, we used brucellaphage DNA as a tool in studying Brucella molecular mechanisms. We engineered two plasmid constructs containing reversely oriented genomic parts of brucellaphage Iz1 and introduced these plasmids into Brucella suis. We showed that one of the two orientations endowed silencing of the luciferase reporter operon activity. We found that this silencing of activity is due to the presence of complementary RNA to the luciferase operon. This is the first time inhibitory RNA is found to act in the Brucella spp. We propose exploiting this mechanism in development of novel vaccines, drugs and diagnostic techniques.
