Role of Bacterial Lipocalin Proteins in Antimicrobial Resistance

BcnA lipocalin, and associated proteins BcoA cytochrome and BarA reductase are involved in membrane peroxidation stress response to antibiotics and other forms of oxidative stress. I report that bcnA, bcoA and barA deletion mutants<br>display enhanced membrane lipid peroxidation and fail to survive under conditions that stimulate peroxidative stress (e.g. Tellurite treatment, cold stress and salt stress). Peroxidation also affects the functionality of the bacterial outer membrane.

Absence of BcnA compromises the permeability of the outer membrane, resulting in the release of extracellular DNA leading to a depletion aggregation phenotype and cell death. Together, my findings uncover a novel peroxidation quenching mechanism based on B. cenocepacia BcnA, BcoA and BarA, which protects the bacterial cell envelope against lipid peroxidation stimulated by antibiotic or metal stress, in the presence of oxygen.