Fresenius Medical Care AG & Co. (NYSE: FMS) is set to become the majority shareholder of Sound Inpatient Physicians Inc. as part of a $600 million recapitalization deal.

Sound Physicians has more than 1,000 doctor partners that provide care in hospitals and acute care centers in the U.S.

For Fresenius, the deal adds to its services which so far include dialysis clinics, vascular care centers, renal pharmacies and laboratories. The Waltham, Massachusetts-based company also recently acquired MedSpring Urgent Care Centers, which operates 14 centers in Illinois and Texas.

Private equity firm TowerBrook Capital Partners will still own a minority stake in sound after the transaction closes within the next 10 days.

The transaction underscores the physician-group M&A activity trend. Recent physician group deals include Envision Healthcare Holdings Inc.'s (NYSE: EVHC) acquisition of Phoenix Physicians LLCin June, and Surgery Center Holdings Inc.'s purchase of Symbion Holdings Corp., also in June. For more on why physician groups are consolidating, see "ACA Reshuffles the Deck" and "ACA Accelerates Physician Group Consolidation."