A microbiological survey of handwashing sinks in the hospital built environment reveals differences in patient room and healthcare personnel sinks

Abstract

Handwashing sinks and their associated premise plumbing are an ideal environment for pathogenharboring biofilms to grow and spread throughout facilities due to the connected system of wastewater plumbing. this study was designed to understand the distribution of pathogens and antibiotic resistant organisms (ARO) within and among handwashing sinks in healthcare settings, using culturedependent methods to quantify Pseudomonas aeruginosa, opportunistic pathogens capable of growth on a cefotaxime-containing medium (OPP-C), and carbapenem-resistant Enterobacteriaceae (CRE). Isolates from each medium identified as P. aeruginosa or enterobacteriaceae were tested for susceptibility to aztreonam, ceftazidime, and meropenem; Enterobacteriaceae were also tested against ertapenem and cefotaxime. isolates exhibiting resistance or intermediate resistance were designated ARO. Pathogens were quantified at different locations within handwashing sinks and compared in quantity and distribution between healthcare personnel (Hcp) and patient room (pR) sinks. ARo were compared between samples within a sink (biofilm vs planktonic samples) and between sink types (HCP vs. PR). The drain cover was identified as a reservoir within multiple sinks that was often colonized by pathogens despite daily sink cleaning. P. aeruginosa and opp-c mean log 10 cfU/cm 2 counts were higher in p-trap and tail pipe biofilm samples from HCP compared to PR sinks (2.77 ± 2.39 vs. 1.23 ± 1.62 and 5.27 ± 1.10 vs. 4.74 ± 1.06) for P. aeruginosa and OPP-C, respectively. P. aeruginosa and opp-c mean log 10 cfU/ml counts were also higher (p < 0.05) in HCP compared to PR sinks p-trap water (2.21 ± 1.52 vs. 0.89 ± 1.44 and 3.87 ± 0.78 vs. 3.21 ± 1.11) for P. aeruginosa and OPP-C, respectively. However, a greater percentage of ARo were recovered from pR sinks compared to Hcp sinks (p < 0.05) for Enterobacteriaceae (76.4 vs. 32.9%) and P. aeruginosa (25.6 vs. 0.3%). This study supports previous work citing that handwashing sinks are reservoirs for pathogens and ARO and identifies differences in pathogen and ARO quantities between HCP and PR sinks, despite the interconnected premise plumbing. From 2014 to 2017, 21.6% of Centers for Disease Control and Prevention (CDC), Division of Healthcare Quality Promotion consultations involved water-related healthcare-associated infections (HAI). Among these investigations, 29.9%, 18.7%, and 10.4% were attributed to nontuberculous mycobacteria (NTM), Pseudomonas spp., and members of the Enterobacteriaceae family, respectively 1. Plumbing fixtures, such as sinks, showers and toilets, with which patients, visitors, and healthcare personnel (HCP) interact are known reservoirs for pathogenic and opportunistic organisms 2-4. Previous work has documented the role that these plumbing fixtures have played in outbreaks, many of which have involved gram-negative rods, such as Pseudomonas spp. and carbapenem-resistant or extended-spectrum β-lactamase producing (ESBL) Enterobacteriaceae 5-9 .

Hospital sink traps as a potential source of the emerging multidrug-resistant pathogen Cupriavidus pauculus: characterization and draft genome sequence of strain MF1

“…pauculus is an emerging human pathogen, having previously been chiefly isolated from soil and aquatic environments. Here, we present its isolation from a hospital sink trap -a niche known to act as a reservoir of pathogens in clinical settings and contribute to nosocomial transmission [36][37][38][39][40]. This study reports the draft hybrid genome sequence of the isolate and investigates its antimicrobial susceptibility, virulence in an in vivo model, and biofilm formation in relevant conditions compared to a wellcharacterized biofilm-forming model organism.…”

“…Sink traps (also known as U-bends or P-traps) are sections of wastewater plumbing systems (WPS), both domestic and commercial, designed to trap water and prevent unwanted flow of sewer gases into the sink and surrounding environment. Sinks are present in virtually all hospital wards and patient rooms to encourage best practice regarding hand hygiene [34,35], however these sink traps become heavily colonized with pathogenic bacteria and are an important reservoir of pathogens causing nosocomial infections [36][37][38][39][40]. The formation of biofilms, which are refractory to disinfection and facilitate long-term persistence of bacteria, poses an additional concern [41].…”

Development and Validation of a High-Throughput Short Sequence Typing Scheme forSerratia marcescensPure Culture and Environmental DNA

“…marcescens strain. This link is supported by the proximity of both sinks in the NICU, with the same drain connection and interconnection through handwashing (57,58). These case studies illustrate the strengths of the HiSST scheme to identify clones and its broad applicability for epidemiological investigations.…”

“…This situation was observed in sinks #72 and #73 for dominants ASV ( bssA -ST 36, gabR -ST 18, dhaM -ST 2) that are likely colonized by the same S. marcescens strain. This link is supported by the proximity of both sinks in the NICU, with the same drain connection and interconnection through handwashing (57, 58). The sink #PLM shared two ST detected in sinks #72 and #73 ( bssA -ST 36 and dhaM -ST 2) and two ST in sink #80 ( gabR -ST 2 and dhaM -ST 2).…”

Methicillin-resistant Staphylococcus aureus contamination of high-touched surfaces in a university campus

“…aureus and MRSA in the environmental samples collected from these areas. This idea is supported by the strong ability of all the MRSA isolates recovered from sinks to form biofilm, as these isolates might have been dispersed from biofilms that can grow from the sink traps to the drain cover (Franco et al, 2020). Our findings raise the potential concern of Staph.…”