Nurses at three Prince George's County health facilities, including the county's largest hospital, went on strike yesterday after contract negotiations between their union and hospital management broke down over the weekend.

About 60 percent of the more than 200 registered nurses who were scheduled to work the day and evening shifts at Prince George's General Hospital, Greater Laurel-Beltsville Hospital and Bowie Health Center joined the walkout, according to union and hospital officials. Nineteen of 54 nurses scheduled to staff 11 p.m. shifts at Prince George's General and Laurel-Beltsville reported to work, officials said. About 650 registered nurses work at the three facilities, and union officials predicted more nurses would join the strike as their shifts were scheduled to start.

The Prince George's strike is the area's largest by nurses since the walkout at Washington Hospital Center in 1978, which eventually involved 60 percent of about 450 nurses.

In response to yesterday's strike, the private association that manages the three facilities closed four of five outpatient clinics at Prince George's General, hired at least eight new nurses, brought in other nurses from outside the area and required nurse supervisors to work 12-hour shifts. Officials of Community Hospital and Health Systems Inc. said, however, that the strike poses no danger to patients already in the hospital, and that essential nursing tasks were being performed by professional employes.

The number of patients at Prince George's General is a bit lower than usual for this time of year, according to hospital officials, with only 360 of that facility's 550 beds filled yesterday. But the relationship of that lower number to the strike was unclear.

"I think everyone has slowed down on elective admissions, even as of last Friday," said Dr. Brian Bailey, a vascular surgeon at Prince George's General. He said that if the strike continues, he and many of his colleagues may schedule their surgery at Doctors or Leland hospitals.

Dr. James E. Abell, an obstetrician at Prince George's General, said last night, "The level of patient care is adequate," adding: "I hate to see nurses on the picket line."

Vascular surgeon Steven Sandler said yesterday's surgery schedule was not affected by the strike, but he said he could not guess what affect it will have as the strike continues.

Rumors that striking nurses would be fired circulated through the picket lines yesterday afternoon at the three facilities, according to Carol Bragg, a union spokeswoman. "They are scared to death," about losing their jobs, Bragg said.

Hospital corporation President Robert J. Brady Jr. said he had not fired anyone. But he added that this week he would begin hiring some nurses in specialty areas such as intensive care and obstetrics.

"If we give a vacant position to a person here, then the person out there on the picket line could be out of a job," he said.

The strike followed a walkout vote Saturday night by about 400 nurses, all members of the Maryland Nurses Association. Seven months of negotiations had failed to produce a new contract. The old contract expired Aug. 14.

"We knew people were mad. We were overwhelmed with the response," Bragg said of Saturday's meeting.

At issue are job responsibilities, an agency shop provision that would require all registered nurses to pay dues even if they do not belong to the union, and wages.

The last offer the corporation made Friday night would increase nurses' hourly wages 35 cents immediately and another 35 cents next July. The proposed 17-month contract would, on average, increase salaries $2,000, hospital spokesman Mike Canning said. Salaries now range from $17,300 to $23,300, according to union President Carolyn Larkin, and are among the lowest in the metropolitan area.

"It was very difficult for us here to make the decision to strike," said Amy Kaplan, an emergency nurse at Laurel-Beltsville who was picketing yesterday. Kaplan said nurses in Laurel have fewer problems because the hospital, with 160 beds, is small and the nurse-patient ratio is low enough to allow nurses to get to know their patients personally. Nurses at Prince George's General say they have too many patients, not enough nurses, and are responsible for many housekeeping chores.

Many of the striking nurses are single parents, according to Larkin. Larkin said she has "encouraged everybody to get another job," either another temporary nursing job or a waitress job. "I don't want anyone going hungry," she said.