B-253. Short-Term Antibiotic Treatment Alters the Long-Term Diversity of the Mouse Intestinal Microbiome

D. A. Antonopoulos1, C. Holmes2, S. M. Huse2, H. G. Morrison2, T. M. Schmidt3, M. L. Sogin2, V. B. Young1;
1The Univ. of Michigan, Ann Arbor, MI, 2The Marine Biological Lab., Woods Hole, MA, 3Michigan State Univ., East Lansing, MI.

Despite their common clinical use, the broader impact of antibiotics on the overall community structure of the gut microbiome has been largely unexplored. It is clear that perturbations of the gut microbiome plays a key role in antibiotic-associated Clostridium difficile colitis. Furthermore, the problem of recurrent C. difficile colitis suggests that antibiotics can lead to prolonged abnormalities in this complex microbial community. In the present study we asked the simple question, does the structure of the resident microbiota exhibit resiliency allowing it to return to its pre-antibiotic treatment composition? C57BL/6 IL-10-/- mice were treated for ten days with either a combination of amoxicillin, metronidazole, and bismuth (AMB) or the broad-spectrum antibiotic cefoperazone (CEF). Separate groups of animals were sacrificed immediately after the antibiotic course or following a drug free period of recovery. In addition to conventional clone libraries, a tag sequencing strategy targeting the V6 hypervariable region of the bacterial small-subunit ribosomal RNA combined with massively parallel sequencing generated over one million amplicons from DNA extracted from the ceca of the mice. Each antibiotic treatment resulted in a marked decrease in diversity characterized by both a decrease in overall richness as well as a shift to a distinctly different composition. However, once the antibiotic selective pressure was relieved, the ability of the community to recover differed based on the antibiotic administered. For the mice that had been treated with AMB there was a significant return towards the pre-antibiotic composition (primarily members of the Bacteroidetes and Firmicutes). In contrast, for the CEF treated mice, a persistent decrease in community diversity relative to the pre-antibiotic community was encountered even after a six week recovery period. This demonstrates that severe antibiotic pressure can produce long-lasting alterations in the gut microbial community and underscores the importance of judicious antibiotic administration strategies.

162/B. Physiology and Metabolism of Pathogenic Microorganisms

Tuesday, 1:00 pm | Poster Hall