The role of copA alone or in combination with other copper resistance genes has been evaluated in animal models of infection for numerous pathogenic gram-negative and gram-positive bacteria, and copA was found to be required for virulence in some bacteria (Acinetobacter baumannii, Klebsiella pneumoniae, Streptococcus pneumoniae, Pseudomonas aeruginosa, Streptococcus agalactiae and Salmonella enterica serovar Typhimurium) (20, –, 26), but not in all cases. The gene discussed is COPA; the disease is infection.