Relation between the lipid composition of Brucella membrane and the resistance to cationic peptides

Abstract

The members of the genus Brucella are α-2 Proteobacteria that cause brucellosis, an important zoonosis. These bacteria trigger only low proinflammatory responses during early infection that allows them to reach sheltered intracellular niches before effective immunity activation. The outer membranes (OM) of brucellae are of critical importance in this strategy. The OM of B. abortus is unusually resistant to antimicrobial peptides (AMPs). Brucella lipopolysaccharide (LPS) is implicated in this property and there is evidence that other lipids (such as phosphatidylcholine) also contribute. Furthermore, these bacteria have acyl chains of average number of carbon units which leads an increase in hydrophobicity, proposed as a biophysical factor underlining AMPs resistance.