title: Whole genome sequencing reveals high-resolution epidemiological links between clinical and environmental Klebsiella pneumoniae.
abstract: Klebsiella pneumoniae is a gram-negative bacterial species capable of occupying a broad range of environmental and clinical habitats. Known as an opportunistic pathogen, it has recently become a major causative agent of clinical infections worldwide. Despite growing knowledge about the highly diverse population of K. pneumoniae, the evolution and clinical significance of environmental K. pneumoniae, as well as the relationship between clinical and environmental K. pneumoniae, are poorly defined.
  
  
  
  We isolated and sequenced K. pneumoniae from in-patients in a single hospital in Thailand, as well as hospital sewage, and surrounding canals and farms within a 20-km radius.
  
  
  
  Phylogenetic analysis of 77 K. pneumoniae (48 clinical and 29 non-clinical isolates) demonstrated that the two groups were intermixed throughout the tree and in some cases resided in the same clade, suggesting recent divergence from a common ancestor. Phylogenetic comparison of the 77 Thai genomes with 286 K. pneumoniae from a global collection showed that Thai isolates were closely related to the clinical sub-population of the global collection, indicating that Thai clinical isolates belonged to globally circulating lineages. Dating of four Thai K. pneumoniae clades indicated that they emerged between 50 and 150 years ago. Despite their phylogenetic relatedness, virulence factors and β-lactamase resistance genes were more numerous in clinical than in environmental isolates. Our results indicate that clinical and environmental K. pneumoniae are closely related, but that hospitals may select for isolates with a more resistant and virulent genotype.
  
  
  
  These findings highlight the clinical relevance of environmental K. pneumoniae isolates.
authors.affiliation: Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.
authors.forename: Chakkaphan
authors.initials: C
authors.lastname: Runcharoen
authors.affiliation: Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, UK. dm16@sanger.ac.uk.
authors.forename: Danesh
authors.initials: D
authors.lastname: Moradigaravand
authors.affiliation: Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Box 157, Hills Road, Cambridge, CB2 0QQ, UK.
authors.forename: Beth
authors.initials: B
authors.lastname: Blane
authors.affiliation: Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.
authors.forename: Suporn
authors.initials: S
authors.lastname: Paksanont
authors.affiliation: Division of Clinical Microbiology, Medical Technology Department, Buddhasothorn hospital, Chachoengsao, 24000, Thailand.
authors.forename: Jeeranan
authors.initials: J
authors.lastname: Thammachote
authors.affiliation: Division of Clinical Microbiology, Medical Technology Department, Buddhasothorn hospital, Chachoengsao, 24000, Thailand.
authors.forename: Suthatip
authors.initials: S
authors.lastname: Anun
authors.affiliation: Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, UK.
authors.forename: Julian
authors.initials: J
authors.lastname: Parkhill
authors.affiliation: Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.|Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.
authors.forename: Narisara
authors.initials: N
authors.lastname: Chantratita
authors.affiliation: Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, UK. sjp97@medschl.cam.ac.uk.|Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Box 157, Hills Road, Cambridge, CB2 0QQ, UK. sjp97@medschl.cam.ac.uk.|London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK. sjp97@medschl.cam.ac.uk.
authors.forename: Sharon J
authors.initials: SJ
authors.lastname: Peacock
mesh_terms: D014644:Genetic Variation; D016680:Genome, Bacterial; D007711:Klebsiella pneumoniae / Q000235:genetics* / Q000302:isolation & purification; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013785:Thailand; D037521:Virulence Factors; D018440:beta-Lactam Resistance
chemical_list: D037521:Virulence Factors
keywords: Antibiotic resistance; Genomic epidemiology; Klebsiella pneumoniae; Whole genome sequencing