Detection of Legionella Anisa in Water from Hospital Dental Chair Units and Molecular Characterization by Whole-Genome Sequencing

Giuseppe Fleres; Natacha Couto; Mariette Lokate; Luc W M van der Sluis; Christophe Ginevra; Sophie Jarraud; Ruud H Deurenberg; John W Rossen; Silvia García-Cobos; Alex W Friedrich

doi:10.3390/microorganisms6030071

Detection of Legionella Anisa in Water from Hospital Dental Chair Units and Molecular Characterization by Whole-Genome Sequencing

Microorganisms. 2018 Jul 18;6(3):71. doi: 10.3390/microorganisms6030071.

Authors

Affiliations

¹ Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, Groningen 9712 CP, The Netherlands. g.fleres@umcg.nl.
² Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, Groningen 9712 CP, The Netherlands. n.monge.gomes.do.couto@umcg.nl.
³ Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, Groningen 9712 CP, The Netherlands. m.lokate@umcg.nl.
⁴ Center of Dentistry and Oral Hygiene, University Medical Center Groningen, 9712 CP Groningen, The Netherlands. l.w.m.van.der.sluis@umcg.nl.
⁵ International Center for Infectiology Research (CIRI), Inserm, U1111, CNRS, UMR5308, ENS de Lyon, Université Claude Bernard Lyon 1, 69007 Lyon, France. christophe.ginevra@univ-lyon1.fr.
⁶ Institute for Infectious Agents, National Reference Centre for Legionella, Groupement Hospitalier Nord, Hospices Civils de Lyon, 69007 Lyon, France. christophe.ginevra@univ-lyon1.fr.
⁷ International Center for Infectiology Research (CIRI), Inserm, U1111, CNRS, UMR5308, ENS de Lyon, Université Claude Bernard Lyon 1, 69007 Lyon, France. sophie.jarraud@univ-lyon1.fr.
⁸ Institute for Infectious Agents, National Reference Centre for Legionella, Groupement Hospitalier Nord, Hospices Civils de Lyon, 69007 Lyon, France. sophie.jarraud@univ-lyon1.fr.
⁹ Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, Groningen 9712 CP, The Netherlands. ruuddeurenberg@home.nl.
¹⁰ Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, Groningen 9712 CP, The Netherlands. john.rossen@gmail.com.
¹¹ Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, Groningen 9712 CP, The Netherlands. s.garcia.cobos@umcg.nl.
¹² Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, Groningen 9712 CP, The Netherlands. alex.friedrich@umcg.nl.

Abstract

This study aims to assess contamination with Legionella spp. in water from dental chair units (DCUs) of a hospital dental ward and to perform its molecular characterization by whole-genome sequencing (WGS). We collect eight water samples (250 mL) from four DCUs (sink and water-syringe). Samples are tested for the presence of Legionella spp. (CFUs/mL) by culturing according to the Nederland Norm (NEN) 6265. Three DCUs are found positive for Legionella anisa, and four isolates are cultured (sink n = 2, water-syringe n = 1; two isolates from the same chair) with 1 × 10² CFU/mL. Whole-genome multi-locus sequence typing (wgMLST) results indicate that all strains belong to the same cluster with two to four allele differences. Classical culture combined with WGS allows the identification of a unique clone of L. anisa in several DCUs in the same hospital dental ward. This may indicate a common contamination source in the dental unit waterlines, which was fixed by replacing the chairs and main pipeline of the unit. Our results reveal tap water contamination in direct contact with patients and the usefulness of WGS to investigate bacterial molecular epidemiology.

Keywords: Legionella spp.; core-genome multi-locus sequence typing (cgMLST); next-generation sequencing (NGS); whole-genome multi-locus sequence typing (wgMLST); whole-genome sequencing (WGS).