Health & Medicine - Posted by Jim Scott CU-Boulder on Tuesday, June 22, 2010 15:22 - 1 Comment 
(No Ratings Yet)
Loading ...
(No Ratings Yet) Loading ...Babies’ first bacteria depend on birth method
The delivery methods of babies have a big effect on the microbial communities they harbor at birth, findings with potential implications for the health of infants as they grow and develop. (Credit: Alan Bruce)
U. COLORADO (US)—Different delivery methods of newborn babies have a big effect on the types of microbial communities they harbor as they emerge into the world, a new study shows.
Share this article
Email
Republish this article
The text of this article by Futurity is licensed under a Creative Commons Attribution-No Derivatives License.
The findings have potential implications for the heath of infants as they grow and develop. Details are reported in the Proceedings of the National Academy of Sciences (PNAS).
The study, led by the University of Puerto Rico and involving the University of Colorado at Boulder and two Venezuelan institutes, showed that babies delivered vaginally had bacterial communities resembling their mother’s vaginal bacteria, while Caesarian section newborns had common skin bacterial communities.
Researchers believe many of the different microbial communities residing on humans—each of which is personally unique—may help protect individuals from various diseases.
The new findings establish an important baseline for tracking the succession of bacterial communities on babies and their associated effects on human health, says co-lead study author Maria Dominguez-Bello of the University of Puerto Rico.
The bacterial communities of C-section babies were dominated by species from the Staphylococcus genus, most of which are harmless but a few of which can cause severe infections, adds Dominguez-Bello. “These differences we are seeing in this study might be related with increased health risks in C-section babies, although more research is needed.”
Previous studies indicate babies born via C-section can be more susceptible to certain pathogens, allergies, and asthma than newborns born vaginally.
The PNAS study results may help explain the higher incidence of Methicillin-resistant Staphylococcus aureus, or MRSA, in C-section babies, a hard-to-treat bacterial infection that has been increasing in hospitals and clinics in recent years, according to the researchers.
In a 2004 study undertaken in Chicago and Los Angeles County hospitals, between 64 percent and 82 percent of reported cases of MRSA skin infections in newborns occurred in C-section infants. While the World Health Organization has recommended the percentage of births via C-section not exceed 15 percent in any country because of potential medical complications, the rate is much higher in a number of countries, including China at nearly 50 percent and the United States at about 30 percent.
Human microbial communities play an important role in digestion and immune health and are believed to collectively endow us with the essential traits we rely on for such functions, according to the research team. One possibility is that the direct transmission of a mother’s vaginal bacteria onto newborns may act as a defense against diseases by limiting the colonization of more harmful pathogens, they note.
In a related 2009 study led by Rob Knight, a coauthor of the current study and assistant professor at Colorado, researchers developed the first atlas of microbial diversity across the human body in adults, charting wide variations in microbe populations from the forehead and feet to noses and navels of individuals—differences that were not yet apparent in the PNAS newborn study.
One goal of the human bacterial studies is to find out what is normal for healthy people, which should provide a baseline for studies looking at human disease states, says Knight.
“The prospects of learning how differences in individual human microbial communities can be used as a diagnostic tool in biomedicine is frankly quite exciting,” says Knight. “With these new data on babies, we now have a second point in time for comparison.”
“In a sense, the skin of newborn infants is like freshly tilled soil that is awaiting seeds for planting—in this case bacterial communities,” says Noah Fierer of Colorado’s ecology and evolutionary biology department. “The microbial communities that cluster on newborns essentially act as their first inoculation.”
Fierer says that during vaginal births “it appears that the newborns pick up the bacteria from the mothers on the way out. But in C-sections, the bacterial communities of infants could come from the first person to handle the baby, perhaps the father.”
The new study has allowed the researchers “to capture the first moments in time” of infant bacterial communities, says Stanford University’s Elizabeth Costello, co-lead author on the study. “The challenge now is to fill in the rest of the story by tracking microbial communities in infants to toddlers to children and adults over weeks, months, and years to see how they evolve and change,” she says.
The work was supported by the Venezuelan Institute for Scientific Research, the Amazonic Center for Research and Control of Tropical Diseases, the National Institutes of Health, the University of Puerto Rico, the Bill and Melinda Gates Foundation, and the Crohn’s and Colitis Foundation of America.
More news from the University of Colorado: www.colorado.edu/news/
Please wait
It would seem the next testing step would be to swab the newborn as soon as they are out of the womb. The fact that skin bacteria gains a foothold with C-section babies could be due to either the first non-sterile person to handle the baby or to the possibility there is something in the pre-surgery procedure that needs modification.