Contaminated Incubators: Source of a Multispecies Enterobacter Outbreak of Neonatal Sepsis.

The genus Enterobacter includes species responsible for nosocomial outbreaks in fragile patients, especially in neonatal intensive care units (NICUs). Determining the primary source of infection is critical to outbreak management and patient outcomes. In this investigation, we report the management and control measures implemented during an Enterobacter outbreak of bloodstream infections in premature babies. The study was conducted in a French NICU over a 3-year period (2016 to 2018) and included 20 premature infants with bacteremia. The clinical and microbiological characteristics were identified, and whole-genome sequencing (WGS) was performed on bacteremia isolates. Initially, several outbreak containment strategies were carried out with no success. Next, outbreak investigation pinpointed the neonatal incubators as the primary reservoir and source of contamination in this outbreak. A new sampling methodology during "on" or "in use" conditions enabled its identification, which led to their replacement, thus resulting in the containment of the outbreak. WGS analysis showed a multiclonal outbreak. Some clones were identified in different isolation sources, including patients and neonatal incubators. In addition, microbiological results showed a multispecies outbreak with a high prevalence of Enterobacter bugandensis and Enterobacter xiangfangensis. We conclude that the NICU health care environment represents an important reservoir for Enterobacter transmission and infection. Finally, extracting samples from the neonatal incubator during active use conditions improves the recovery of bacteria from contaminated equipment. This method should be used more frequently to achieve better monitoring of the NICU for HAIs prevention.