Role of copper efflux in pneumococcal pathogenesis and resistance to macrophage-mediated immune clearance

Michael D.L. Johnson, Thomas E. Kehl-Fie, Roger Klein, Jacqueline Kelly, Corinna Burnham, Beth Mann, Jason W. Rosch

Research output: Contribution to journalArticlepeer-review

55 Scopus citations


In bacteria, the intracellular levels of metals are mediated by tightly controlled acquisition and efflux systems. This is particularly true of copper, a trace element that is universally toxic in excess. During infection, the toxic properties of copper are exploited by the mammalian host to facilitate bacterial clearance. To better understand the role of copper during infection, we characterized the contribution of the cop operon to copper homeostasis and virulence in Streptococcus pneumoniae. Deletion of either the exporter, encoded by copA, or the chaperone, encoded by cupA, led to hypersensitivity to copper stress. We further demonstrated that loss of the copper exporter encoded by copA led to decreased virulence in pulmonary, intraperitoneal, and intravenous models of infection. Deletion of copA resulted in enhanced macrophage-mediated bacterial clearance in vitro. The attenuation phenotype of the copA mutant in the lung was found to be dependent on pulmonary macrophages, underscoring the importance of copper efflux in evading immune defenses. Overall, these data provide insight into the role of the cop operon in pneumococcal pathogenesis.

Original languageEnglish (US)
Pages (from-to)1684-1694
Number of pages11
JournalInfection and Immunity
Issue number4
StatePublished - 2015

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases


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