Vigorous cleaning and adequate ventilation are necessary to control an outbreak in a neonatal intensive care unit

An outbreak of Bacillus cereus (B. cereus) bacteremia occurred in our neonatal intensive care unit (NICU) in July 2005. Many strains of B. cereus were cultured from patient specimens, as well as from environmental samples such as the surfaces of instruments and air in the NICU. Some of these strains were analyzed by pulsed field gel electrophoresis, and several were confirmed to be identical. We speculated that the bacterial load in the environment had initially increased and then possibly spread throughout the NICU facility via the airflow of the ventilation system. For this reason, besides maintaining standard precautions, we performed a vigorous clean of the NICU, and covered the vents to prevent dust falling from them. These protective measures ended the outbreak. In the hospital environment, adequate ventilation is important, especially in single-occupancy isolation rooms and operating theaters. However, the criteria for the adequate ventilation of multioccupancy rooms for acute care environments such as the NICU have not yet been defined. We need to pay more attention to these environmental factors in order to avoid cross contamination and infectious outbreaks.