The mold problem that closed UPMC Presbyterian's 20-bed cardiothoracic intensive care unit may be more widespread than initially reported, according to an article on the TribLive website.
While it was initially reported that mold was found in a patient's external wound, it was also found in his lung tissue. The Pittsburgh hospital has not said what type of mold was found or what caused it to thrive in the ICU.
Most likely, humidity, water leakage or construction produced the moldy environment, according to the article.
“Construction, as in banging on walls and knocking down foundations, in the hospital could cause mold to be aerated,” a hospital safety expert said. “If there was water leakage behind the walls and water spots did not start appearing, you can't fault the hospital for that.”
Ventilation and Filtering for Infection Control 
ChristianaCare Opens Aston Campus Neighborhood Hospital
Stantec Breaks Ground on New Academic Medical Center in Miami
Building Senior Living for the Next Generation of Retirees
Managing Drain and Biofilm Risk