Wall Street tumbled on Wednesday in its worst day since August, as a spike in Italian bond yields signaled the European debt crisis was getting worse.

The Dow Jones industrial average dropped 389.31 points, or 3.20 percent, to 11,780.87, according to the latest available figures. The Standard & Poor's 500 Index dropped 46.82 points, or 3.67 percent, to 1,229.10. The Nasdaq Composite Index dropped 105.84 points, or 3.88 percent, to 2,621.65.

(Editing by Kenneth Barry)