May 17 (Reuters) - Wall Street’s main indexes opened lower on Monday after a sharp recovery late last week, as signs of inflationary pressures building in the economy kept investors worried about monetary policy tightening. The Dow Jones Industrial Average fell 6.84 points, or 0.02%, at the open to 34,375.29. The S&P 500 opened lower by 3.93 points, or 0.09%, at 4,169.92, while the Nasdaq Composite dropped 61.18 points, or 0.46%, to 13,368.80 at the opening bell. (Reporting by Sruthi Shankar in Bengaluru; Editing by Maju Samuel) Our Standards: The Thomson Reuters Trust Principles.