- Meets the following high-risk criteria: Requires mechanical ventilation at the time of study entry; and has a central venous catheter in place at the time of study entry; and is receiving broad spectrum antibiotics at the time of study entry; AND meets at least one of the following criteria: Required parenteral nutrition during the current ICU admission; or required renal dialysis during the current ICU admission; or had major surgery during or within the 7 days before the current ICU admission; or was diagnosed with pancreatitis during or within the 7 days before the current ICU admission; or required systemic steroids or other immunosuppressive agents during or within the 7 days before the current ICU admission