Metagenomic strain tracking reveals patterns of bacterial spread and the impact of water chlorination

Daehyun D Kim1, Colin J Worby2, Hannah Wharton1

  • 1Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, CA, USA.

Insights

Machine learning tracked bacterial strains in Kenyan children, revealing young children drive pathogen spread. Community water chlorination reduced bacterial sharing, highlighting a key public health intervention for reducing childhood infections.

Area of Science:

  • Microbiology
  • Genomics
  • Public Health

Background:

  • Bacterial infections are a significant cause of illness and death in children under five in low- and middle-income countries (LMICs).
  • Understanding bacterial transmission patterns is crucial for developing effective interventions, but traditional methods are labor-intensive.
  • Metagenomic data offers a powerful tool to study microbial communities and their interactions.

Purpose of the Study:

  • To characterize bacterial dissemination patterns in LMIC communities using a machine learning strain tracking approach.
  • To assess the impact of community-wide water chlorination on bacterial transmission dynamics.
  • To differentiate transmission pathways for various bacterial taxa, including potentially pathogenic and commensal species.

Main Methods:

  • Applied a machine learning strain tracking method to metagenomic data from 511 stool samples of children and mothers in Kenyan communities.
  • Analyzed bacterial strain-sharing dynamics across different species and assessed the influence of factors like age and water treatment.
  • Compared bacterial dissemination in communities with and without water chlorination.

Main Results:

  • Identified distinct strain-sharing patterns for different bacterial species, with potentially pathogenic bacteria disseminated by young children.
  • Commensal bacteria showed transmission patterns linked to dietary exposures.
  • Community-level bacterial strain-sharing was reduced in rural communities with drinking water chlorination.

Conclusions:

  • This study provides the first strain-level insights into multi-species bacterial transmission in LMIC communities, revealing distinct dissemination pathways.
  • Metagenomic strain tracking is a valuable tool for understanding bacterial spread and identifying effective disruption strategies.
  • Water chlorination can be an effective intervention to reduce community-level bacterial transmission.