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Front. Microbiol. | doi: 10.3389/fmicb.2019.00599

Microbiota of the gut-lymph node axis: Depletion of mucosa-associated segmented filamentous bacteria and enrichment of Methanobrevibacter by Colistin sulfate and Linco-Spectin in pigs

  • 1University of Veterinary Medicine Vienna, Austria
  • 2Österreichisches Kompetenzzentrum für Futter- und Lebensmittelqualität, Sicherheit und Innovation, Austria
  • 3Iowa State University, United States

Microorganisms are translocated from the gut to lymphatic tissues via immune cells, thereby challenging and training the mammalian immune system. Antibiotics alter the gut microbiome and consecutively might also affect the corresponding translocation processes, resulting in an imbalanced state between the intestinal microbiota and the host. Hence, understanding the variant effects of antibiotics on the microbiome of gut-associated tissues is of vital importance for maintaining metabolic homeostasis and animal health. In the present study, we analyzed the microbiome of i.) pig feces, ileum, and ileocecal lymph nodes under the influence of antibiotics (Linco-Spectin and Colistin sulfate) using 16S rRNA gene sequencing for high-resolution community profiling and ii) ileocecal lymph nodes in more detail with two additional methodological approaches i.e. cultivation of ileocecal lymph node samples and iii) metatranscriptome sequencing of a single lymph node sample. Supplementation of medicated feed showed a local effect on feces and ileal mucosa-associated microbiomes. Pigs that received antibiotics harbored significantly reduced amounts of segmented filamentous bacteria along the ileal mucosa (p=0.048; 199.17-fold change) and increased amounts of Methanobrevibacter, a methanogenic Euryarchaeote in fecal samples (p=0.005; 20.17-fold change) compared to the control group. Analysis of the porcine ileocecal lymph node microbiome exposed large differences between the viable and the dead fraction of microorganisms and the microbiome was altered to a lesser extent by antibiotics compared with feces and ileum. The core microbiome of lymph nodes was constituted mainly of Proteobacteria. RNA-sequencing of a single lymph node sample unveiled transcripts responsible for amino acid and carbohydrate metabolism as well as protein turnover, DNA replication and signal transduction. The study presented here is the first comparative study of microbial communities in feces, ileum and its associated ileocecal lymph nodes. In each analyzed site, we identified specific phylotypes susceptible to antibiotic treatment that can have profound impacts on the host physiological and immunological state, or even on global biogeochemical cycles. Our results indicate that pathogenic bacteria, e.g. enteropathogenic E. coli, could escape antibiotic treatment by translocating to lymph nodes. In general ileocecal lymph nodes harbor a more diverse and active community of microorganisms than previously assumed.

Keywords: antibiotics, Lymph Node, Ileum, microbiome, 16S rRNA gene, Segmented Filamentous Bacteria (SFB), Gut Microbiota

Received: 04 Sep 2018; Accepted: 08 Mar 2019.

Edited by:

Sergey M. Stolyar, University of Idaho, United States

Reviewed by:

Sandip Paul, Indian Institute of Chemical Biology (CSIR), India
Steve Lindemann, Purdue University, United States  

Copyright: © 2019 Zwirzitz, Pinior, Metzler-Zebeli, Handler, Gense, Knecht, Ladinig, Dzieciol, Wetzels, Wagner, Schmitz-Esser and Mann. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Evelyne Mann, University of Veterinary Medicine Vienna, Vienna, A-1210, Vienna, Austria,