Role of members of the autotransporter family in adhesion and invasion of Brucella suis to host cells

RUIZ, V.; POSADAS, D. M.; MARTÍN, F A; ZORREGUIETA, A

Villa Carlos Paz

Congreso; VI Congreso Argentino de Microbiología General. Sociedad Argentina de Microbiología General; 2009

SAMIGE

Species belonging to the <i>Brucella</i> genera are intracellular pathogens responsible of an endemic disease called brucellosis. Even though the intracellular trafficking of brucellae has been extensively characterized, other stages of the infection process remain unknown. It has been shown that brucellae are able to adhere to model epithelial cells, but the factors involved in the adhesion and/or invasion to these cells remain unexplored. By bioinformatical methods we identified several putative adhesins from the autotransporter family in the genome of <i>Brucella suis</i>.  In this work we assessed the role of three members of the autotransporter family (AubD, AubE and AubF) in the adhesion to an abiotic surface and HeLa cells by heterologous and mutational approaches. Autotransporter genes cloned with their own promoters into pBRRMCS1 were transferred to non-adhesive non-invasive <i>Escherichia coli</i>. The strain of <i>E. coli</i> with cloned <i>aubF</i> showed an enhanced attachment to polystyrene indicating that AubF increase either the attachment to the abiotic surface or adhesion between bacteria. Besides, AubF conferred to <i>E. coli</i> enhanced ability to adhere and invade HeLa cells.  A deletion mutant in the <i>aubD</i> gene showed a dramatic loss in the ability to attach and invade HeLa cells compared with the wild type isogenic strain.  Likewise, deletion of <i>aubE</i> significantly reduced adhesion and invasion to HeLa cells, albeit less marked than the effect caused by the <i>aubD</i> mutation. Taken together, these results strongly suggest that these members of the autotransporter family are involved in the adhesion and/or invasion of <i>B. suis</i> to eukaryotic cells.