Epidemiology of paediatric gastrointestinal colonisation by extended spectrum cephalosporin-resistant Escherichia coli and Klebsiella pneumoniae isolates in north-west Cambodia

BMC Microbiol. 2019 Mar 12;19(1):59. doi: 10.1186/s12866-019-1431-9.

Abstract

Background: Extended-spectrum cephalosporin resistance (ESC-R) in Escherichia coli and Klebsiella pneumoniae is a healthcare threat; high gastrointestinal carriage rates are reported from South-east Asia. Colonisation prevalence data in Cambodia are lacking. The aim of this study was to determine gastrointestinal colonisation prevalence of ESC-resistant E. coli (ESC-R-EC) and K. pneumoniae (ESC-R-KP) in Cambodian children/adolescents and associated socio-demographic risk factors; and to characterise relevant resistance genes, their genetic contexts, and the genetic relatedness of ESC-R strains using whole genome sequencing (WGS).

Results: Faeces and questionnaire data were obtained from individuals < 16 years in north-western Cambodia, 2012. WGS of cultured ESC-R-EC/KP was performed (Illumina). Maximum likelihood phylogenies were used to characterise relatedness of isolates; ESC-R-associated resistance genes and their genetic contexts were identified from de novo assemblies using BLASTn and automated/manual annotation. 82/148 (55%) of children/adolescents were ESC-R-EC/KP colonised; 12/148 (8%) were co-colonised with both species. Independent risk factors for colonisation were hospitalisation (OR: 3.12, 95% CI [1.52-6.38]) and intestinal parasites (OR: 3.11 [1.29-7.51]); school attendance conferred decreased risk (OR: 0.44 [0.21-0.92]. ESC-R strains were diverse; the commonest ESC-R mechanisms were blaCTX-M 1 and 9 sub-family variants. Structures flanking these genes were highly variable, and for blaCTX-M-15, - 55 and - 27 frequently involved IS26. Chromosomal blaCTX-M integration was common in E. coli.

Conclusions: Gastrointestinal ESC-R-EC/KP colonisation is widespread in Cambodian children/adolescents; hospital admission and intestinal parasites are independent risk factors. The genetic contexts of blaCTX-M are highly mosaic, consistent with rapid horizontal exchange. Chromosomal integration of blaCTX-M may result in stable propagation in these community-associated pathogens.

Keywords: Cambodia; Carriage; ESBL; Paediatric.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Anti-Bacterial Agents / pharmacology
  • Cambodia / epidemiology
  • Carrier State / epidemiology*
  • Carrier State / microbiology
  • Cephalosporins / pharmacology*
  • Child
  • Child, Preschool
  • Drug Resistance, Bacterial*
  • Escherichia coli / drug effects
  • Escherichia coli / genetics
  • Escherichia coli / pathogenicity
  • Escherichia coli Infections / epidemiology*
  • Female
  • Gastrointestinal Tract / microbiology*
  • Gastrointestinal Tract / parasitology
  • Hospitalization
  • Humans
  • Klebsiella Infections / epidemiology*
  • Klebsiella pneumoniae / genetics
  • Klebsiella pneumoniae / pathogenicity
  • Male
  • Parasitic Diseases / epidemiology
  • Parasitic Diseases / microbiology
  • Prevalence
  • Risk Factors
  • Surveys and Questionnaires
  • Whole Genome Sequencing

Substances

  • Anti-Bacterial Agents
  • Cephalosporins