Fitch Ratings downgraded by one notch the debt rating of Trinity Health, which owns Mercy Health System of Southeastern Pennsylvania, St. Mary Medical Center in Bucks County, and Lourdes Health System in South Jersey.

The new rating on $5 billion in debt is AA-, which is down from AA, driven by weak margins in the year ended June 30, 2016, along with similar results in the three months ended Sept. 30, Fitch said. The system's outlook was revised to stable from negative.

Including hospitals in Trenton and Wilmington, Trinity's Philadelphia-area operations had $1.9 billion in revenue in fiscal 2016, or 11.6 percent of Trinity's total.