Migration of Escherichia coli and Klebsiella pneumoniae Carbapenemase (KPC)-Producing Enterobacter cloacae through Wastewater Pipework and Establishment in Hospital Sink Waste Traps in a Laboratory Model System

Abstract

Sink waste traps and drains are a reservoir for multi-drug resistant Gram-negative bacteria in the hospital environment. It has been suggested that these bacteria can migrate through hospital plumbing. Hospital waste traps were installed in a laboratory model system where sinks were connected through a common wastewater pipe. Enterobacterales populations were monitored using selective culture, MALDI-TOF identification and antibiotic resistance profiling before and after a wastewater backflow event. When transfer between sinks was suspected, isolates were compared using whole-genome sequencing. Immediately after the wastewater backflow, two KPC-producing Enterobacter cloacae were recovered from a waste trap in which Carbapenemase-producing Enterobacterales (CPE) had not been detected previously. The isolates belonged to ST501 and ST31 and were genetically indistinguishable to those colonising sinks elsewhere in the system. Following inter-sink transfer, KPC-producing E. cloacae ST501 successfully integrated into the microbiome of the recipient sink and was detected in the waste trap water at least five months after the backflow event. Seven weeks and three months after the backflow, other inter-sink transfers involving Escherichia coli ST5295 and KPC-producing E. cloacae ST501 were also observed.

Extended-Spectrum β-Lactamase Genes Traverse the Escherichia coli Populations of Intensive Care Unit Patients, Staff, and Environment

“…Of the three instances where highly similar isolates were found in bed units in different rooms, two (involving ST1193 and ST167) were associated with sinks. Hospital sinks have been shown in other studies to be important reservoirs of antibiotic-resistant pathogens ( 18 , 19 ) and to contribute to transmission via plumbing in model systems ( 20 ).…”

Extended-spectrum β-lactamase genes traverse theEscherichia colipopulations of ICU patients, staff and environment

“…Hospital sinks have been shown in other studies to be important reservoirs of antibiotic-resistant pathogens, 25,26 and to contribute to transmission via plumbing in model systems. 27 Although there was little crossover at strain level between the ICU and clinical collections, some bla CTX-M -bearing plasmid lineages were represented in both, as well as in multiple STs within the ICU surveillance collection. I-complex plasmids (I1 and Z types) were particularly prominent here.…”

“…Hospital sinks have been shown in other studies to be important reservoirs of antibiotic-resistant pathogens, 25,26 and to contribute to transmission via plumbing in model systems. 27…”

Tailpiece Heating device for effective prevention of biofilm growth in sink plumbing

“…or ii) due to retrograde back-flow from the sanitary stack and connecting pipes (Fig 1). These mechanisms for establishing multidrug resistant gram-negative bacteria in the sinks has been experimentally demonstrated previously (14)(15)(16). From a microbiology standpoint the sink wastewater system can be divided into three zones.…”

“…Wastewater systems are designed such that all waste flows down from the sink or toilet, however, moist environments favor establishment and spread of biofilm inside the plumbing even against gravity (14, 16). With this knowledge and an aim to mitigate transmission from sink drain biofilms to the patient care environment, a scientifically informed electronic device was developed.…”