麻豆淫院

Worldwide, more than 500,000 children under age 5 die each year from gastrointestinal bacterial infections, largely in communities with limited access to safe drinking water, sanitation and hygiene infrastructure. But to alleviate this public health threat, scientists need to better understand how these pathogens spread.

Now, a team of UC Berkeley researchers has shown that the household environment might play a larger role in transmission than previously thought. Using a new approach to examine bacterial strain-sharing patterns, they discovered that stored drinking water is a key transmission pathway for E. coli bacteria within and between households in developing countries.

Their findings, in Nature Microbiology, offer fresh insights into the role contaminated drinking water plays in spreading gastrointestinal infections and antibiotic-resistant bacterial strains鈥攁nd may lead to effective mitigation strategies to protect children's health.

According to Amy Pickering, associate professor of civil and environmental engineering and the study's principal investigator, previous studies had focused on the bacteria exchange between animals and humans. Her team decided to explore the role of drinking water and soil as under-studied pathways.

"We were interested in understanding the role of the household environment in bacterial transmission to humans," she said. "And our findings showed that water is actually one of the most important transmission pathways for pathogenic and drug-resistant bacteria."

To see how each of the three main pathways鈥攈uman, animal and environment鈥攃ontribute to bacterial spread in these communities, Pickering's team developed a scalable, high-throughput bacterial strain-tracking method called PIC-seq (Pooled Isolated Colonies-seq). Using this tool, researchers could sequence up to five bacterial strains per sample, instead of the conventional one strain per sample.

"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."

They then studied E. coli strain-sharing patterns within two households located in informal urban settlements in Nairobi, Kenya. These communal settings typically consist of compounds with a shared courtyard. As low-resource communities, they also have limited access to basic services and infrastructure, and household drinking water is often stored in jerry cans and plastic buckets.

The researchers collected human stool, poultry and dog feces, stored water and soil samples from each household. They then cultured E. coli colonies from the samples and used PIC-seq to analyze the different strains.

"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 and lead author of the study. "These findings underscore that the environment can play just as significant a role in bacterial transmission as animals鈥攐r even more so."

While analyzing the contaminated drinking water, the researchers also identified E. coli strains carrying high-risk antibiotic resistance genes. Such genes could be passed to other bacteria through horizontal gene transfer, enabling the spread of antibiotic-resistant strains within the community, another serious health threat.

In addition, the study offered clues about potential mitigation strategies. Households with access to chlorinated water showed a lower rate of E. coli contamination in stored drinking water. Based on these findings, the researchers suggest that community-level chlorinated water may offer a practical approach to preventing the spread of bacterial and drug-resistant strains between household members as well as between different households.

"Overall, our study's findings highlight the importance of safe drinking water in mitigating the spread of pathogenic and antibiotic-resistant bacteria," said Kim, "which is critical to safeguarding children's health in these communities."