Nutrients influence the dynamics of Klebsiella pneumoniae carbapenemase producing enterobacterales in transplanted hospital sinks

Shireen Meher Kotay,Hardik I Parikh,Katie Barry,Hyun Soon Gweon,William Guilford,Joanne Carroll,Amy J Mathers

doi:10.1016/j.watres.2020.115707

Abstract

Antimicrobial resistance has been recognized as a threat to human health. The role of hospital sinks acting as a reservoir for some of the most concerning antibiotic resistant organisms, carbapenemase producing Enterobacterales (CPE) is evident but not well understood. Strategies to prevent establishment, interventions to eliminate these reservoirs and factors which drive persistence of CPE are not well established. We use a uniquely designed sink lab to transplant CPE colonized hospital sink plumbing with an aim to understand CPE dynamics in a controlled setting, notably exploiting both molecular and culture techniques. After ex situ installation the CPE population in the sink plumbing drop from previously detectable to undetectable levels. The addition of nutrients is followed by a quick rebound in CPE detection in the sinks after as many as 37 days. We did not however detect a significant shift in microbial community structure or the overall resistance gene carriage in longitudinal samples from a subset of these transplanted sinks using whole shotgun metagenomic sequencing. Comparing nutrient types in a benchtop culture study model, protein rich nutrients appear to be the most supportive for CPE growth and biofilm formation ability. The role of nutrients exposure is determining factor for maintaining a high bioburden of CPE in the sink drains and P-traps. Therefore, limiting nutrient disposal into sinks has reasonable potential with regard to decreasing the CPE wastewater burden, especially in hospitals seeking to control an environmental reservoir.

Highlights

tryptic soy broth (TSB) spiked with 0.1 mg/mL cefepime (TSB_cef), was found to be most growth promoting across the four species
We found that nutrients appear to play a critical role in Klebsiella pneumoniae producing Enterobacterales (KPCE) abundance in real world hospital drain biofilms once transplanted into a sink lab
While we demonstrate that with just soap and water the burden of KPCE decreased to undetectable levels in transplanted sinks, we do not know the threshold number of bacteria on a sink drain that are needed to cause a dispersion with a faucet event

Summary

Introduction

Escalating number of reports on contamination of hospital sinks with multidrug-resistant gram-negative organisms, and recent scientific investigations establishing their link to outbreaks and transmissions to patients, underline the role of these environmental reservoirs in managing healthcare associated infections (Amoureux et al, 2017; Bousquet et al, 2017; De Geyter et al, 2017; Herruzo et al, 2017; Hopman et al, 2017; Leitner et al, 2015; Lowe et al, 2012; Regev-Yochay et al, 2018; Roux et al, 2013; Starlander and Melhus, 2012; Tofteland et al, 2013; Varin et al, 2017; Vergara-Lopez et al, 2013; Yablon et al, 2017). The primary mechanism of transmission from sinks to patients has recently been demonstrated in a model lab using a model organism (Kotay et al, 2017). Other reports have highlighted the potential risks of disposal of nutrients into the patient sinks in the form of beverages, IV fluids, body fluids and other liquid wastes (De Geyter et al, 2017; Leitner et al, 2015; Lowe et al, 2012; Roux et al, 2013; Smolders et al, 2018)

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