Serratia marcescens outbreak in a neonatal intensive care unit related to the exit port of an oscillator

To interrupt transmission of Serratia marcescens colonization in a neonatal intensive care unit and determine the source of ongoing transmission. Multidisciplinary outbreak investigation and simulation of droplet generation by a high-frequency oscillator using fluorescent dye. Level III neonatal intensive care unit. Very low birth weight premature infants with respiratory failure. Infection control interventions, pulsed-field gel electrophoresis of isolates to determine relatedness, and construction of a scavenging system to capture the circuitry condensate expelled by the oscillator exit port. Affected infants were housed in the same geographic site. Serratia marcescens isolates were indistinguishable or closely related using pulsed-field gel electrophoresis. Fluorescent droplet splatter from the circuitry, generated when no containment device covered the exit valve, was visible up to 49 in (107.8 cm) from the source. Implementation and adherence to infection control measures is essential to prevent transmission of opportunistic pathogens among ventilated infants. Oscillators can generate droplets that travel farther than 1 m from the source.