The sink as a potential source of transmission of carbapenemase-producing Enterobacteriaceae in the intensive care unit

Abstract

BackgroundCarbapenemase-producing Enterobacteriaceae (CPE) are emerging pathogens that represent a major public health threat. In the University Hospital of Brussels, the incidence of new patients with CPE rose from 1 case in 2010 to 35 cases in 2015. Between January and August 2015, five patients became infected/colonized with CPE during their stay in the same room in the intensive care unit (ICU). Since the time period between those patients was relatively short and the strains belonged to different species with different antibiograms and mechanisms of resistance, the hypothesis was that the environment could be a possible source of transmission.Methods and resultsEnvironmental samples suggested that a contaminated sink was the source of the outbreak. Besides other strains, Citrobacter freundii type OXA-48 was frequently isolated from patients and sinks. To investigate the phylogenetic relationschip between those strains, pulsed-field gel electrophoresis was performed. The strains isolated from patients and the sink in the implicated room were highly related and pointed to sink-to-patient transmission. In total, 7 of 8 sinks in the isolation rooms of the ICU were found to be CPE contaminated. To control the outbreak, the sinks and their plumbings were replaced by new ones with another structure, they were flushed every morning with a glucoprotamin solution and routines regarding sink practices were improved leading to discontinuation of the outbreak.ConclusionsThis outbreak highlights that hospital sink drains can accumulate strains with resistance genes and become a potential source of CPE.

Droplet rather than Aerosol Mediated Dispersion is the Primary Mechanism of Bacterial transmission from Contaminated Hand Washing Sink Traps

“…The objective of the present study was to characterize the mechanism of bacterial dispersion from handwashing sinks, using a GFP plasmid-containing E. coli strain as a surrogate for multidrug resistant Enterobacteriaceae. Very few studies have investigated the dispersion from sinks using methods to sample aerosol-associated microorganisms(23, 36, 40, 41); however, several studies have drawn subjective interpretations about aerosol-mediated transmission from contaminated sinks(3, 6, 10, 13, 21, 37). Doring et al used an impaction method to examine P. aeruginosa dispersion from the sink bowl surface during faucet use.…”

“…De Geyter et al used an MAS-100 air sampler to measure CRE dispersal from contaminated sinks with and without faucet usage. Several species in the family Enterobacteriaceae were detected during faucet usage but results for control samples (without faucet usage) were not provided(23). Fusch et al in contrast sampled air around sinks with and without faucet event (control) and did not detect P. aeruginosa in air samples collected without running water(36).…”

“…This further underlines the importance of sanitary hygiene practices, strategic surveillance paired with hand washing only use of hand-washing sinks in the patient care environment to reduce the risk of hand-washing sink contamination by the multi-drug-resistant microorganisms that can colonize ICU patients(8). This also emphasizes the necessity to implement stricter measures to prohibit disposal of nutrients, body fluids and anything into the sinks that could be a nutrient source for maintenance of microorganism biofilms in drains(23). Dispersion from a contaminated sink reservoir can result in transmission to patients either directly or indirectly mediated through numerous contact surfaces.…”

“…Factors effecting the rate and extent of droplet-mediated dispersion were investigated, but particle size involved in dispersion was not measured in this study. Studies that claim aerosols as the primary dispersion mechanism from sinks are based on rudimentary findings (2, 23, 35, 36) or assumptions drawn based on these unsubstantiated findings(3, 6, 10, 13, 21, 37). Airborne particles originating from sinks can have varied sizes and compositions.…”

Klebsiella quasipneumonaiae provides a window into carbapenemase gene transfer, plasmid rearrangements and nosocomial acquisition from the hospital environment

“…There is increasing recognition that the hospital environment is an important potential reservoir in the transmission of carbapenemase-producing Enterobacteriaceae (CPE), but delineating transmission chains is often challenging(17, 18). Through our K. quasipneumoniae example we provide compelling evidence for patient-to-drain and drain-to-patient transmission, as has been observed in other studies(7).…”