Seeding and establishment of legionella pneumophila in hospitals: Implications for genomic investigations of nosocomial legionnaires' disease

Sophia David, Baharak Afshar, Massimo Mentasti, Christophe Ginevra, Isabelle Podglajen, Simon R. Harris, Victoria Chalker, Sophie Jarraud, Timothy Harrison, Julian Parkhill*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

Background. Legionnaires' disease is an important cause of hospital-acquired pneumonia and is caused by infection with the bacterium Legionella. Because current typing methods often fail to resolve the infection source in possible nosocomial cases, we aimed to determine whether whole-genome sequencing (WGS) could be used to support or refute suspected links between cases and hospitals. We focused on cases involving a major nosocomial-associated strain, L. pneumophila sequence type (ST) 1. Methods. WGS data from 229 L. pneumophila ST1 isolates were analyzed, including 99 isolates from the water systems of 17 hospitals and 42 clinical isolates from patients with confirmed or suspected hospital-acquired infections, as well as isolates obtained from or associated with community-acquired sources of Legionnaires' disease. Results. Phylogenetic analysis demonstrated that all hospitals from which multiple isolates were obtained have been colonized by 1 or more distinct ST1 populations. However, deep sampling of 1 hospital also revealed the existence of substantial diversity and ward-specific microevolution within the population. Across all hospitals, suspected links with cases were supported with WGS, although the degree of support was dependent on the depth of environmental sampling and available contextual information. Finally, phylogeographic analysis revealed that hospitals have been seeded with L. pneumophila via both local and international spread of ST1. Conclusions. WGS can be used to support or refute suspected links between hospitals and Legionnaires' disease cases. However, deep hospital sampling is frequently required due to the potential coexistence of multiple populations, existence of substantial diversity, and similarity of hospital isolates to local populations.

Original languageEnglish
Pages (from-to)1251-1259
Number of pages9
JournalClinical Infectious Diseases
Volume64
Issue number9
DOIs
Publication statusPublished - 1 May 2017

Bibliographical note

Publisher Copyright:
© The Author 2017.

Keywords

  • Bacterial genomics
  • Legionella pneumophila
  • Legionnaires' disease
  • Nosocomial infections
  • Whole-genome sequencing

Fingerprint

Dive into the research topics of 'Seeding and establishment of legionella pneumophila in hospitals: Implications for genomic investigations of nosocomial legionnaires' disease'. Together they form a unique fingerprint.

Cite this