• The Outer Membrane Factor of Brucella suis is involved in antimicrobial resistance and virulence

POSADAS, DM.; MARTÍN, FA.; SABIO GARCÍA, J.; SPERA, JM.; CRAVERO, S. AND ZORREGUIETA, A

Congreso; SAIB XLII; 2006

Brucella spp., like other pathogens must cope with the environment of diverse host niches during the infection process. In doing this, pathogens evolved different tyoe of transporter systems to help them survive and disseminate within the host. Members of the Outer Membrane Factor (OMF) in association with two inner-membrane proteins were shown to be involved in the export of chemically diverse molecules. The role of proteins of this family was little explored in Brucella; to analyze its biological relevance we performed heterologous complementation assays; the gene coding the unique B. suis OMF protein (Bep) was cloned and expressed in the tolC mutant of E.coli. Bep fully complemented the resistance to drugs such as chloranfenicol and acriflavine, but was unable to restore hemolysin secretion in this mutant. An insertion mutant was constructed in B.suis and the sensitivity to several drugs was analyzed, as well as the virulence in diverse models; the mutation in the bep gene strongly affected the resistance phenotype to bile salts and toxic chemicals and significatively decreased the resistance to antibiotics such as erithromycin, tetracyclin and norfloxacin. Moreover, the bep mutant of B.suis was attenuated in the mice model. Taking together, these results suggest that in B.suis, the efflux processes that are bep dependent contribute to survival inside the host.