Testing the waters
Worldwide, more than 500,000 children under age five die each year from gastrointestinal bacterial infections, largely in communities lacking safe drinking water, sanitation and hygiene infrastructure. To address this public health threat, scientists need to better understand how these pathogens spread.
Now, a team led by Amy Pickering, associate professor of civil and environmental engineering, has discovered that stored drinking water is a key transmission pathway for E. coli bacteria in developing countries.
To see how humans, animals and environmental factors contribute to bacterial spread, the researchers developed a bacterial strain-tracking method called Pooled Isolated Colonies-seq (PIC-seq). This tool can sequence up to five bacterial strains per sample, instead of the conventional one strain, allowing for a more detailed analysis.
“PIC-seq proved to be a game changer,” said Pickering. “It enabled us to get more comprehensive views of within and between household strain sharing.”
Researchers used the method to study E. coli strain-sharing patterns in households in Nairobi, Kenya, consisting of compounds with a common courtyard.
“We found a higher level of strain-sharing between humans and stored drinking water than between humans and domesticated animals within households,” said Daniel Daehyun Kim, a postdoctoral researcher. “These findings underscore that the environment can play just as significant a role in bacterial transmission as animals — or even more so.”
Learn more: Household drinking water identified as key pathway for bacterial transmission; Contaminated drinking water facilitates Escherichia coli strain-sharing within households in urban informal settlements (Nature Microbiology)