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

Abstract

Objective: To interrupt transmission of Serratia marcescens colonization in a neonatal intensive care unit and determine the source of ongoing transmission.

Design: Multidisciplinary outbreak investigation and simulation of droplet generation by a high-frequency oscillator using fluorescent dye.

Setting: Level III neonatal intensive care unit.

Patients: Very low birth weight premature infants with respiratory failure.

Interventions: 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.

Measurements and main results: 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.

Conclusions: 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.