Characterization of a New putative virulence factor of Brucella abortus

DOHMER, PETER H.; CZIBENER C; UGALDE JE

Sapporo

Congreso; XIII International Congress of Bacteriology and Applied Microbiology; 2011

International Union of Microbiological Societies

Brucella is an intracellular bacterial pathogen that causes abortion and infertility in mammals and leads to a debilitating febrile illness that can progress into a chronic disease in humans. Virulence depends on the capacity to survive within the host cell and to achieve this it has developed strategies to escape recognition by the innate immunity and to modulate the immune response. The mechanisms of virulence of Brucella spp. are not yet fully understood, and therefore, it is crucial to identify new virulence factors in order to develop novel prophylactic and/or therapeutic methods. The aim of this work was to study and characterize a new putative virulence factor involved in the intracellular replication on host cells. Applying a bioinformatic approach we searched the Brucella genome for novel virulence factors identifying genomic regions with transposons or recombinases close to transfer RNA genes indicative of possible horizontal transfer. With this approach we identified gene Bab1_1492, with unknown function and no conserved domains. A tagged version of Bab1_1492 allowed us to determine that the protein is secreted from the bacteria during infection and that, most probably, localizes to the Brucella containing vacuole. A deletion mutant strain showed altered intracellular replication kinetics, with reduced intracellular bacteria in the initial stages and higher ones at later time points compared to the wild-type.