Addicted to antibiotics, Chile's salmon flops at Costco, grocers

A pool containing dead salmon is seen at a salmon production plant which was damaged by lahar from Calbuco Volcano at Correntoso near Chamiza April 25, 2015. REUTERS/Ivan Alvarado

SANTIAGO (Reuters) - Chile's salmon farmers are using record levels of antibiotics to treat a virulent and pervasive bacteria, driving away some U.S. retailers including Costco Wholesale Corp, which is turning to antibiotic-free Norwegian salmon.

The coastal waters of Chile, the world's second-largest producer of salmon, are awash with a bacteria known as SRS, or Piscirickettsiosis. The bacteria causes lesions and haemorrhaging in infected fish, and swells their kidneys and spleens, eventually killing them.