CopA Protects against Copper Toxicity.

is a zoonotic pathogen that causes great economic losses to the swine industry and severe threats to public health. A better understanding of its physiology would contribute to the control of its infections. Although copper is an essential micronutrient for life, it is toxic to cells when present in excessive amounts. Herein, we provide evidence that CopA is required for resistance to copper toxicity. Quantitative PCR analysis showed that expression was specifically induced by copper. Growth curve analyses and spot dilution assays showed that the Δ mutant was defective in media supplemented with elevated concentrations of copper. Spot dilution assays also revealed that CopA protected against the copper-induced bactericidal effect. Using inductively coupled plasma-optical emission spectroscopy, we demonstrated that the role of CopA in copper resistance was mediated by copper efflux. Collectively, our data indicated that CopA protects against the copper-induced bactericidal effect via copper efflux.