Nurses represented by the California Nurses Association Monday started a Christmas Eve strike at a number of Bay Area hospitals over contract disputes.

The one-day strike stems from disputes with Sutter Health and HCA Healthcare over issues including health benefits, sick pay and staffing levels.

"When profit comes at the expense of patients and their own work force, then there is something terribly wrong," union spokeswoman Joanne Jung said.

The union started picket lines at all nine hospital campuses at 7 a.m. and closed the lines at 3 p.m. so that picketers could go home to prepare for the Christmas holiday, but the strike itself would go on until 7 a.m. Tuesday, Jung said.

Dozens of nurses scheduled to work at Good Samaritan Hospital and Regional Medical Center of San Jose joined the picket lines Monday morning at both hospitals, which are owned by HCA Healthcare, Jung said.

An unknown number of nurses were participating in the strike at six hospitals owned by Sutter Health, including two Alta Bates Summit Medical Center facilities in Berkeley and Oakland, Eden Medical Center in Castro Valley and its affiliate San Leandro Hospital, Sutter Solano Medical Center in Vallejo and Sutter Delta Medical Center in Antioch, Jung said.

The hospitals together employ about 5,000 nurses who are represented by the CNA, Jung said.

Leslie Kelsay, a spokeswoman for Good Samaritan Hospital in San Jose, where a similar strike was held on Thanksgiving Day, said the hospital has hired about 300 contracted replacement nurses who worked Monday and the next four days in place of striking nurses.

Regular nurses who participated in the strike would not be allowed to work until 7 a.m. on Dec. 29, Kelsay said.

About 60 union nurses opted to cross the picket line at Good Samaritan that morning, she said.

HCA has had more than 30 bargaining sessions with the union since May and labor leaders decided to strike even after agreeing to meet with a federal mediator in January, Kelsay said.

"It's not going to be resolved at the sidewalk or the parking lot, but only at the negotiating table," Kelsay said.