In a finding that may one day help control a major cause of death among
children in developing countries, a team of researchers led by faculty
from the University of Maryland, College Park and the University of
Maryland School of Medicine has identified microorganisms that may
trigger diarrheal disease and others that may protect against it. These
microbes were not widely linked to the condition previously.
"We were able to identify
interactions between microbiota that were not previously observed, and
we think that some of those interactions may actually help prevent the
onset of severe diarrhea," says O. Colin Stine, a professor of
epidemiology and public health at the University of Maryland School of
Medicine.
A much better understanding of these interactions is
important, Stine adds, as they could lead to possible dietary
interventions. Moderate to severe diarrhea (MSD) is a major cause of
childhood mortality in developing countries and ranks as one of the top
four causes of death among young children in sub-Saharan Africa and
South Asia.
Stine and Mihai Pop, an associate professor of
computer science at the University of Maryland, College Park led the
six-year project funded by $10.1 million from the Bill & Melinda
Gates Foundation. The research results are available in a paper
published in the journal Genome Biology.
The researchers
used a technique called high-throughput 16S rRNA genomic sequencing to
examine both "good" and "bad" microbiota -- the tens of trillions of
microbes that inhabit the human intestinal system -- in samples taken
from 992 children in Bangladesh, The Gambia, Kenya and Mali under the
age of 5 who were suffering from MSD.
The researchers identified
statistically significant disease associations with several organisms
already implicated in diarrheal disease, such as members of the
Escherichia/Shigella genus and Campylobacter jejuni.
They also found that organisms not widely believed to cause the disease,
including Streptococcus and Granulicatella, correlated with the
condition in their study. In addition, the study revealed that the
Prevotella genus and Lactobacillus ruminis may play a protective role against diarrhea.
The
project is an offshoot of a $20 million study commissioned by the Gates
Foundation in 2006. The Global Enterics Multicenter Study (GEMS) was
launched in response to unanswered questions surrounding the burden and
etiology of childhood diarrhea in developing countries.
GEMS
collected troves of useful data on MSD, yet there were still some
uncertainties, says Pop, who also has an appointment in the University
of Maryland Institute for Advanced Computer Studies.
For example,
in almost 50 percent of the children examined with diarrhea, the
condition could not be attributed to a specific causal pathogen. The
GEMS research also found numerous children carrying Shigella, which is
known to cause problems, yet the children showed no signs of MSD.
The
Gates Foundation contacted the two University of Maryland scientists in
2007, looking for new analyses of the GEMS data via a combination of
computational biology, epidemiology and public health.
"New
technologies have opened up new windows of discovery, so they asked us
to look at the samples," says Pop, who adds that he and Stine expect to
conduct further genomic and epidemiological studies to assess the
potential development of diet- or microbiological-based therapeutics.
Journal Reference:
- Mihai Pop, Alan W Walker, Joseph Paulson, Brianna Lindsay, Martin Antonio, M Hossain, Joseph Oundo, Boubou Tamboura, Volker Mai, Irina Astrovskaya, Hector Bravo, Richard Rance, Mark Stares, Myron M Levine, Sandra Panchalingam, Karen Kotloff, Usman N Ikumapayi, Chinelo Ebruke, Mitchell Adeyemi, Dilruba Ahmed, Firoz Ahmed, Meer Alam, Ruhul Amin, Sabbir Siddiqui, John B Ochieng, Emmanuel Ouma, Jane Juma, Euince Mailu, Richard Omore, J Morris, Robert F Breiman, Debasish Saha, Julian Parkhill, James P Nataro, O Stine. Diarrhea in young children from low-income countries leads to large-scale alterations in intestinal microbiota composition. Genome Biology, 2014; 15 (6): R76 DOI: 10.1186/gb-2014-15-6-r76
Courtesy: ScienceDaily
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