SEOUL, South Korea -- The heir of the Samsung business empire bowed deep in apology Tuesday as criticism mounted over a Samsung hospital's role in spreading Middle East respiratory syndrome in South Korea.

Lee Jae-yong, 47, apologized to MERS victims and patients in his first public speech since taking over the Samsung Foundation last month. He succeeded his ailing father in leading the charity foundation that owns Samsung Medical Center.

Out of 175 MERS patients in South Korea, 85 were patients, relatives, staff or visitors at the Samsung hospital in Seoul. One of the MERS patients was a Samsung contract worker who was not quarantined and continued to work at the hospital until confirmed to have the disease.

Samsung Medical Center, one of the largest hospitals in South Korea, draws patients from around the country. The hospital stopped receiving patients last week.

"Our Samsung Medical Center could not stop the infection and the spread of MERS, causing so much pain and worry for the public," Lee said in a rare public speech that was televised nationwide on his 47th birthday. "I bow my head to apologize."

The MERS outbreak has killed 27 people since May.

In an editorial last week, South Korea's largest daily newspaper Chosun Ilbo called for an investigation into possible ties between authorities and Samsung Medical Center, asking why health officials did not step in early to oversee the hospital's response to the disease.

The spread of MERS through Samsung Medical Center is a major embarrassment for Lee who is expected to inherit South Korea's largest business group from his father.

Market watchers believe that Lee, vice chairman at Samsung Electronics Co. but not on the company's board, has yet to prove his ability to lead a conglomerate that does business in consumer electronics, shipbuilding, insurance, construction and amusement parks.

His father Lee Kun-hee, 73, chairman at Samsung Electronics Co., has been hospitalized at Samsung Medical Center since suffering a heart attack in May last year.(AP)