Hundreds of registered nurses walked off the job and formed picket lines in front of East Bay hospitals Friday morning to begin a seven-day strike against institutions affiliated with Sutter Health.

The hospitals brought in replacement workers and planned to remain open during the walkout.

This marks the ninth time since September 2011 that members of the California Nurses Association/National Nurses United have gone on strike at Sutter hospitals in the East Bay.

The dispute centers around wages, benefits and patient care issues.

Five hospitals with more than 2,800 nurses are affected, including three Alta Bates Summit Medical Center facilities in Oakland and Berkeley, Eden Medical Center in Castro Valley and Sutter Delta Medical Center in Antioch.

At the last minute, the union withdrew plans to strike San Leandro Hospital after learning that Sutter plans to transfer ownership of the facility to the Alameda Health System, which runs Highland Hospital in Oakland.

The union has reached agreements with other Sutter hospitals in San Mateo, San Francisco, Sonoma, Marin and Lake counties, but has been unable to come to terms with leaders of East Bay institutions.

Sandy Kleffman covers health. Contact her at 510-293-2478. Follow her at Twitter.com/skleffman.