COLUMBUS, Ohio — Two unions representing tens of thousands of Ohio workers said Monday they would no longer support the state’s only Democratic congressman to oppose President Barack Obama’s health care bill.

U.S. Rep. Zack Space betrayed union members who campaigned for him in 2006 and 2008, said the Service Employees International Union and the United Food and Commercial Workers union.

“A no vote on health care is an anti-worker vote,” said Allison Petonic, spokeswoman for Columbus-based UFCW Local 1059, which has 18,000 members working in food retailing and processing in Ohio. That includes 1,500 people living in Space’s district, she said.

Space was among 54 Democrats who voted against the landmark legislation Sunday. It passed 219-212 with no Republican support.

Space said over the weekend that he had serious reservations about the measure and that he feared it might financially burden the working class by “opening the door to taxing employee benefits as income.”

The Democrat, who represents a conservative, Appalachian district, said a version of the bill he supported last year taxed wealthy Americans, not the middle class, to help pay some health care costs for the working poor.

The unions were unconvinced.

“Working class, middle income people who live in the congressman’s district really need help to obtain their health care. While this bill isn’t perfect, it’s step in the right direction,” said Anthony Caldwell, spokesman for SEIU District 1199, which represents about 25,000 hospital, nursing home, state and other workers in Ohio.

Messages seeking comment were left Monday for Space’s press secretary, Andrew Ricci.

“I think it was a tough vote for him,” said freshman Rep. Steve Driehaus, who spoke with Space on the House floor Sunday night but declined to discuss the nature of their conversation.