Pseudooutbreak of Candida guilliermondii fungemia in a neonatal intensive care unit.

During a 3-week period multiple blood cultures obtained from 14 Neonatal Intensive Care Unit infants and 3 Newborn Unit babies grew Candida guilliermondii, a yeast rarely associated with infections in humans. At the time of detection of positive cultures, most infants had been hospitalized for days or weeks for serious perinatal conditions and treated with antibiotics and intravenous hyperalimentation. Two critically ill premature infants from whom the yeast was isolated were given amphotericin B. In 7 other infants, however, yeasts were recovered on the day of birth, raising the question of pseudofungemia. Exhaustive interrogation on the blood culture practices revealed that when drawing blood for a culture from small infants, "butterfly" needles were often flushed with a diluted heparin solution to prevent blood clotting. Culture of a single lot of diluted heparin vials, prepared at the hospital pharmacy and distributed to the Neonatal Intensive Care Unit and Newborn Unit shortly before the onset of the epidemic, grew between 10,000 and 15,000 colony-forming units of Candida guilliermondii/ml. Removal of contaminated heparin vials and discontinuation of heparinization of needles used for blood cultures resulted in cessation of the epidemic. The present outbreak illustrates the difficulties in recognizing pseudoinfections in sick premature infants and the importance of intensive investigation and intervention during such an outbreak.