Orlando-area Congresswoman Suzanne Kosmas will abandon fellow Democrats and vote against the health care bill, the first known defection from Florida.

"While the health care reform bill before the U.S. House of Representatives has many positive elements, I believe that it does not do enough to slow the growth of health care costs and spending on care. Therefore, after careful consideration and with great difficulty, I have decided that I cannot support the legislation," she said in a statement.

Her decision, while expected, is still striking given the passionate call for Democrats to stand together on the landmark issue. But Kosmas took her seat last November from Republican Tom Feeney and she already has a number of GOP challengers.

House Speaker Nancy Pelosi is not demanding lockstep support from her caucus, allowing some vulnerable members to stray. She needs 218 votes out of 256 Democrats. Pelosi will have the backing of another Orlando-area Democrat, who also took a Republican seat in 2008, U.S. Rep. Alan Grayson, the self-styled "congressman with guts."