Swiss food conglomerate Nestlé SA has agreed to sell several North American regional spring water brands, including Maine-based Poland Spring, to a pair of private equity firms for $4.3 billion. The buyers are an affiliate of One Rock Capital Partners LLC, a New York-based investment firm focused on high-potential middle market businesses, and Metropoulos & Co., a family-owned backer of several food and beverage brands including Hostess Brands, Utz snacks, Pabst Brewing Co. beer and Ghirardelli Chocolates. A spokesman for Nestlé was not immediately available to comment on interest from other potential suitors or when talks with that led to the transaction began. Coca-Cola Co. and PepsiCo Inc. had previously been cited by Bloomberg News as potential buyers for the brands.