McKesson Corp., the No. 1 drug wholesaler in the U.S., said fiscal first-quarter operating income rose sharply from a year ago, beating Wall Street estimates and boosting its stock. In the quarter ended June 30, San Francisco-based McKesson reported a 30% increase in operating income to $48.7 million, or 49 cents per diluted share. Wall Street analysts had expected 47 cents per share. A year ago, the company earned $37.6 million, or 39 cents per diluted share. Including special items for its pending acquisition of rival AmeriSource Health Corp., McKesson’s earnings rose 12% to $42.1 million from $37.6 million a year earlier.