We are born alone.
But soon bacteria, viruses and others crowd in, creating our first microbiota. These essentials will determine many aspects of our future health.
A mission this monumental is sadly given little planning or thought. Vaginal delivery which immediately seeds the newborn with its mother’s microflora is preferred yet often mothers and their doctors choose a surgical cesarean section just for the convenience (and in the United States, to avoid malpractice suits). Also, while many mothers breastfeed their infants, many opt out, bypassing the perfect nutrition for baby.
Antibiotics change the early gut microbiome too.
Anjelique Schulfe and Martin J. Blaser of New York University published Risks of Antibiotic Exposures Early in Life on the Developing Microbiome in PLOS July 2, 2015.
Some of the key points covered:
- First microbiota are very unstable and have little diversity.
- As first foods are introduced, the microbiota blooms in richness, adding different organisms to the mix. Soon, at 3 years or so, the whole mélange can resemble an adult’s.
- Each is unique, created by genetics and environment. Nature vs. nurture.
- When antibiotics disturb that environment, a torrent of changes are set in motion, each as unique as the individual.
Some examples cited by the authors:
- “After seven days of clindamycin treatment, patients had significantly reduced diversity of the Bacteroides community compared with the pretreatment microbiota that remained distinctive two years after antibiotic cessation .”
- “Similarly, in addition to decreasing bacterial diversity, a five day course of ciprofloxacin changed relative abundance of 30% of the gut microbiota community members.”
How long were the effects?
Four weeks for some, but more than 6 months for others. And when two courses were given, recovery was even longer.
The community changes. Some losses—like losing all our teachers—are devastating; others show that organisms can substitute for the vanquished ones, a concept called functional redundancy. An example from the authors notes that a single streptomycin dose reduced metabolites needed to make bile acids.
Long term changes are thought to follow:
Early microbes impact stem-cells. Recall that stem cells await their marching orders: fat, muscle, bone or immune. Microbes help fashion those pathways. And antibiotics can change them, often for a lifetime. Serious repercussions, indeed.
Antibiotics can also change the numbers of antibiotic-resistant genes, an effect which may last years. These changes may set the infant up for autoimmune diseases such as asthma, allergies, arthritis, and multiple sclerosis: T cell populations in the gut can be influenced by the microbiota and its metabolites.
Evidence to support this is growing, thanks to sophisticated database mining. Antibiotic use is linked to inflammatory bowel disease, diabetes, asthma, multiple sclerosis as well as weight changes and vulnerability to infection.
The authors conclude that while antibiotics are wonder drugs they should be better understood and used. Also, when antibiotics are necessary, perhaps reseeding is in order: fecal samples taken before can be reintroduced later, like refugees from the storm.