Antibiotics Disrupt Gut Flora in Infants: Recovery Still Incomplete After Eight Weeks

[Oliver Crangle]

Antibiotics Disrupt Gut Flora in Infants: Recovery Still Incomplete
After Eight Weeks

Nov. 8, 2012 — Eight weeks after antibiotic treatment of infants, the
diversity of gastrointestinal flora remained diminished, although the
number of individual bacteria was back to normal, according to a paper
in the November 2012 issue of the journal Antimicrobial Agents and
Chemotherapy. Additionally, the potentially disease-causing
Proteobacteria were now the dominant population in the treated
infants.

"This is the first sequencing-based study to demonstrate the negative
effects of short-term antibiotic treatment on the beneficial gut
bacteria populations in infants," says coauthor Catherine Stanton of
the Teagasc Food Research Centre, Fermoy, Cork, Ireland.

In the study, nine infants were treated with intravenous ampicillin/
gentamicin within 48 hours of birth, and over the two month study
period, their gastrointestinal flora were compared to that in nine
control infants. At four weeks, bacteria from the beneficial genera,
the Bifidobacteria and the Lactobacilli, were significantly reduced,
and although the numbers bounced back by the study's end, the species
diversity did not. The researchers used advanced DNA sequencing to
identify the species of gut flora, and to quantify their numbers, says
Stanton.

By altering the gut microbiota, and thus the immune system very early
in life, the antibiotics could negatively influence long-term health,
particularly by boosting the risk of developing asthma, allergy, and
obesity, according to the report. The risk is heightened by the fact
that the antibiotic-driven disruption of the microbiota comes at a
time "when this population is in rapid flux and can easily be
unbalanced," according to the report.

These results notwithstanding, because the sequencing data reveal only
proportions of species present, rather than absolute numbers, it
remains unclear whether the potentially harmful Proteobacteria
predominate because their population has grown or because the other
populations have shrunk, the researchers write. However, the data
suggest the former, which jibes with previous research.

"This research suggests that the merits of administering broad
spectrum antibiotics -- those that kill many bacterial species -- in
infants should be reassessed, to examine the potential to use more
targeted, narrow-spectrum antibiotics, for the shortest period
possible," says Stanton.

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Story Source:

The above story is reprinted from materials provided by American
Society for Microbiology.

Note: Materials may be edited for content and length. For further
information, please contact the source cited above.

Journal Reference:

F. Fouhy, C. M. Guinane, S. Hussey, R. Wall, C. A. Ryan, E. M.
Dempsey, B. Murphy, R. P. Ross, G. F. Fitzgerald, C. Stanton, P. D.
Cotter. High-Throughput Sequencing Reveals the Incomplete, Short-Term
Recovery of Infant Gut Microbiota following Parenteral Antibiotic
Treatment with Ampicillin and Gentamicin. Antimicrobial Agents and
Chemotherapy, 2012; 56 (11): 5811 DOI: 10.1128/AAC.00789-12





http://www.sciencedaily.com/releases/2012/11/121108195409.htm