Carbapenemase-producing Enterobacterales in hospital drains in Southern Ontario, Canada

J Hosp Infect. 2020 Dec;106(4):820-827. doi: 10.1016/j.jhin.2020.09.007. Epub 2020 Sep 9.

Abstract

Background: Hospital drains may be an important reservoir for carbapenemase-producing Enterobacterales (CPE).

Aim: To determine prevalence of CPE in hospital drains exposed to inpatients with CPE, relatedness of drain and patient CPE, and risk factors for drain contamination.

Methods: Sink and shower drains in patient rooms and communal shower rooms exposed to 310 inpatients with CPE colonization/infection were cultured at 10 hospitals. Using short- and long-read whole-genome sequencing, inpatient and corresponding drain CPE were compared. Risk factors for drain contamination were assessed using multi-level modelling.

Findings: Of 1209 exposed patient room and communal shower room drains, 53 (4%) yielded 62 CPE isolates in seven (70%) hospitals. Of 49 CPE isolates in patient room drains, four (8%) were linked to prior room occupants. Linked drain/room occupant pairs included Citrobacter freundii ST18 isolates separated by eight single nucleotide variants (SNVs), related blaKPC-containing IncN3-type plasmids (different species), related blaKPC-3-containing IncN-type plasmids (different species), and related blaOXA-48-containing IncL/M-type plasmids (different species). In one hospital, drain isolates from eight rooms on two units were Enterobacter hormaechei separated by 0-6 SNVs. Shower drains were more likely to be CPE-contaminated than hand hygiene (odds ratio: 3.45; 95% confidence interval: 1.66-7.16) or patient-use (13.0; 4.29-39.1) sink drains. Hand hygiene sink drains were more likely to be CPE-contaminated than patient-use sink drains (3.75; 1.17-12.0).

Conclusion: Drain contamination was uncommon but widely dispersed. Drain CPE unrelated to patient exposure suggests contamination by undetected colonized patients or retrograde (drain-to-drain) contamination. Drain types had different contamination risks.

Keywords: Carbapenem-resistant Enterobacterales; Communicable diseases; Disease reservoirs; Emerging; Infection control.

MeSH terms

  • Bacterial Proteins
  • Drug Resistance, Bacterial
  • Enterobacter / isolation & purification*
  • Enterobacteriaceae Infections / prevention & control
  • Equipment Contamination*
  • Hospitals*
  • Humans
  • Ontario
  • Patients' Rooms*
  • Water Supply*
  • beta-Lactamases

Substances

  • Bacterial Proteins
  • beta-Lactamases
  • carbapenemase

Supplementary concepts

  • Enterobacter hormaechei