Uneasy Truce

People and their microbes have long coexisted, mainly in an uneasy peace. While bacteria can cause disease — Helicobacter pylori is behind gastric ulcers — the lack of bacteria is also being linked to disease, writes Michael Specter in this week's issue of The New Yorker. As little as 15 years ago, some doctors were saying that "the only good Helicobacter pylori is a dead Helicobacter pylori."

Now, though, Specter adds, that as the numbers of people infected with H. pylori have dropped, asthma rates have increased, as have obesity rates. Of course, he notes that correlation should not be confused with causation, but he says the evidence is mounting.

The connection between peoples' health and their microbiome is complex and intertwined, but may also offer treatment possibilities by re-introducing microbes lost to due to antibiotic use back into people. "We will need to make sure that pregnant women have to appropriate microbial communities to pass on to their children. If they don't we will have to give them to the kids after they are born," New York University's Martin Blaser says. "Then, for certain bacteria like Helicobacter, at the age of thirty or forty, they could go to a clinic and have them eradicated. That way, people can get the benefit of these organisms in early like without having to pay the cost as they age."