150 people have now contracted the virus in South Korea.
The 38-year-old man started showing symptoms such as diarrhoea, fever and skin lesions after arriving in the Slovak capital of Bratislava on 3 June.
More than 70 cases have been traced back to the hospital, authorities say.
The hospital said: “Among the cases was an emergency ward orderly who worked for days after developing symptoms, coming into contact with more than 200 people.”
“We sincerely apologize with our heads bent to the people for causing great concern as Samsung Medical Center became the center (of) the spread of MERS,” hospital President Song Jae-hoon said.
The number of people who have come into contact with patients and put under quarantine either at state facilities or at home has risen to 5,200.
“We are doing our best to stop the spread of MERS,” said the Korean minister of health. “We are analyzing the CCTV with the help of Busan police,” referring to tracking down who had been at the hospitals.