Babies lack microbes in their intestinal tracts at birth. Scientists have shown that infants establish their communities of gut microbes through ingestion of microorganisms from their environment from crawling on the floor, for example, to putting toys and other objects into their mouths, to nursing and other contacts with their primary caregivers.
Dantas and his colleagues have been leaders in the development of functional metagenomics, in which scientists identify and analyze all the DNA from a microbial community. Instead of focusing either only on individual cultured organisms or computationally predicting functions from DNA sequences, researchers experimentally screen the DNA for specific functions, such as antibiotic resistance.
Dantas' primary research interest is the ecology and evolution of antibiotic resistance. According to a recent report by the Centers for Disease Control and Prevention, antibiotic-resistant infections cause at least 2 million illnesses and 23,000 deaths annually, adding $20 billion in health-care costs. Dantas noted that methicillin-resistant Staphylococcus aureus, one of the most dangerous antibiotic-resistant bacteria, now causes more deaths in the United States than HIV. Scientists use the term resistome to refer to the collective antibiotic resistance genes of a microbial community.
"There were quite a few resistance genes in microbes from every child we looked at," Dantas said. "This was true even in children who were only six months old. When we compared their resistomes to those of older children, there didn't seem to be much difference."
Dantas' results, which must be confirmed through additional testing, suggest the resistome in the gut may become fixed more quickly than the distribution of speci
|Contact: Michael C. Purdy|
Washington University School of Medicine