title: Spread from the Sink to the Patient:In SituStudy Using Green Fluorescent Protein (GFP)-Expressing Escherichia coli To Model Bacterial Dispersion from Hand-Washing Sink-Trap Reservoirs.
abstract: There have been an increasing number of reports implicatingGammaproteobacteriaas often carrying genes of drug resistance from colonized sink traps to vulnerable hospitalized patients. However, the mechanism of transmission from the wastewater of the sink P-trap to patients remains poorly understood. Herein we report the use of a designated hand-washing sink lab gallery to model dispersion of green fluorescent protein (GFP)-expressingEscherichia colifrom sink wastewater to the surrounding environment. We found no dispersion of GFP-expressingE. colidirectly from the P-trap to the sink basin or surrounding countertop with coincident water flow from a faucet. However, when the GFP-expressingE. colicells were allowed to mature in the P-trap under conditions similar to those in a hospital environment, a GFP-expressingE. coli-containing putative biofilm extended upward over 7 days to reach the strainer. This subsequently resulted in droplet dispersion to the surrounding areas (<30 in.) during faucet operation. We also demonstrated that P-trap colonization could occur by retrograde transmission along a common pipe. We postulate that the organisms mobilize up to the strainer from the P-trap, resulting in droplet dispersion rather than dispersion directly from the P-trap. This work helps to further define the mode of transmission of bacteria from a P-trap reservoir to a vulnerable hospitalized patient.IMPORTANCEMany recent reports demonstrate that sink drain pipes become colonized with highly consequential multidrug-resistant bacteria, which then results in hospital-acquired infections. However, the mechanism of dispersal of bacteria from the sink to patients has not been fully elucidated. Through establishment of a unique sink gallery, this work found that a staged mode of transmission involving biofilm growth from the lower pipe to the sink strainer and subsequent splatter to the bowl and surrounding area occurs rather than splatter directly from the water in the lower pipe. We have also demonstrated that bacterial transmission can occur via connections in wastewater plumbing to neighboring sinks. This work helps to more clearly define the mechanism and risk of transmission from a wastewater source to hospitalized patients in a world with increasingly antibiotic-resistant bacteria that can thrive in wastewater environments and cause infections in vulnerable patients.
authors.affiliation: Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia, USA.
authors.forename: Shireen
authors.initials: S
authors.lastname: Kotay
authors.affiliation: Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia, USA.
authors.forename: Weidong
authors.initials: W
authors.lastname: Chai
authors.affiliation: Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA.
authors.forename: William
authors.initials: W
authors.lastname: Guilford
authors.affiliation: Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia, USA.
authors.forename: Katie
authors.initials: K
authors.lastname: Barry
authors.affiliation: Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia, USA ajm5b@virginia.edu.|Clinical Microbiology, Department of Pathology, University of Virginia Health System, Charlottesville, Virginia, USA.
authors.forename: Amy J
authors.initials: AJ
authors.lastname: Mathers
mesh_terms: D018441:Biofilms; D003428:Cross Infection / Q000382:microbiology / Q000517:prevention & control; D004197:Disease Reservoirs / Q000382:microbiology; D024881:Drug Resistance, Bacterial; D004866:Equipment Contamination; D004926:Escherichia coli / Q000737:chemistry / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000635:transmission*; D049452:Green Fluorescent Proteins / Q000032:analysis*; D006235:Hand Disinfection; D006760:Hospitalization; D006801:Humans; D007297:Inpatients; D062065:Wastewater / Q000382:microbiology*
chemical_list: D049452:Green Fluorescent Proteins; D062065:Wastewater
keywords: antibiotic resistance; biofilms; dispersion; hand washing; hospital infections; premise plumbing; sink; transmission; wastewater