ST. PAUL, Minn. – The Minnesota Nurses Association reached a tentative contract agreement that could avert a strike against major hospitals in the Twin Cities and Duluth areas. The union, representing 15,000 nurses, was prepared to strike Sunday. The union president, Mary Turner, said the most significant point in the agreement gives nurses a voice in staffing. The deal, if approved by the union membership, would raise salaries 17% to 18% over three years.