The agency had to close a system of labs called PulseNet that track illnesses. Those labs are now back open.
Two hundred seventy eight people in 18 states have been sickened by the outbreak -- most of them in California. The CDC says 42 percent have been hospitalized, about double the normal rate. Some of the strands were resistant to antibiotics, so some people could not be easily treated.
The outbreak is connected to Foster Farms chicken produced in California. The USDA mark on suspect packages would read: P6137, P6137A and P7632.