1221. Stenotrophomonas maltophilia Outbreak Associated with Sink Drains in an Intensive Care Unit

Abstract

Background Stenotrophomonas maltophilia (SMA) is an opportunistic pathogen that causes significant morbidity and mortality and has been associated with outbreaks in various hospital environments. We describe an outbreak of SMA in our intensive care unit (ICU) and highlight the sink drain as the probable source of SMA. Methods Clinical surveillance for hospital-acquired infections due to SMA was instituted in December of 2017, when a cluster of cases was identified in our ICU. We first performed an environmental survey in random sites in our ICU rooms: high-touch surfaces, drains in handwashing sinks, clean water, enteral feeding, and ice machines. SMA was only found in the sink drain. We then performed an environmental survey focused on sink drains and the surrounding areas. We identified rooms where patients positive for SMA were previously hospitalized. Sampling sites were standardized for all rooms: bed rail, sink drain, splash zone, and air near sinks. Bed rails were swabbed with sponge-swabs and sink drains with flocked swabs with liquid Amies transport media. Swab samples were cultured in broth and solid media. Splash zone samples were collected using MacConkey agar plates left for four hours immediately adjacent and at one foot from the sink. Air samples were also collected for 10 minutes onto MacConkey agar plates using EMD Millipore MAS-100 NT impactor air sampler. All media was incubated aerobically at 35-37°C. Identification of all isolated gram-negative organisms was performed using MALDI-TOF MS. Results Five rooms were surveyed (Table 1). All rooms were found to have medical supplies within the splash zone. 100% (5/5) of sink drain samples had SMA recovered in culture, compared to 10% (1/10) of splash zone samples, 20% (1/5) of air samples, and 20% (1/5) of bed rails. In addition, we isolated other gram-negative organisms. We repeated the environmental survey after placing a sink drain cover in rooms found to have SMA in areas other than the drain. In the follow-up survey, we found no growth in cultures except for air samples (Table 2). Conclusion Sink drains pose a risk for SMA, possibly via contamination of medical supplies near sinks. Further investigation, including sequencing of environmental and clinical isolates, is needed to understand the mode of transmission. Disclosures All Authors: No reported disclosures.

Stenotrophomonas maltophilia Outbreak in an ICU: Investigation of Possible Routes of Transmission and Implementation of Infection Control Measures

“…In our study, the presence of S. maltophilia was documented in a single location (trolley in Box 2). The detection of S. maltophilia in limited environmental settings aligns with findings from other studies [29][30][31]. In our investigation, the presence of S. maltophilia was detected in seven patients.…”