PP04-2 3,4,4'-Trichlorocarbanilide Exposure Induces Gut Microbial Dysbiosis in Neonatal Rats

Program: Abstracts - Orals, Poster Previews, and Posters
Session: PP04-Endocrine Disrupting Chemicals
Friday, April 1, 2016: 11:30 AM-11:45 AM
Room 258 (BCEC)

Poster Board FRI 105
Rebekah C Kennedy*1, Russell R Fling1, Michael Robeson2, Arnold M Saxton1, David Bemis1, Jiang Liu1, Ling Zhao1 and Jiangang Chen1
1University of Tennessee, Knoxville, TN, 2Colorado State University, Fort Collins, CO
The use of prescription antibiotics during pregnancy and birth can induce alterations in the maternal bacterial milieu and contribute to the disturbance of neonatal microbial colonization. The assumed risk of infectious disease during pregnancy and lactation additionally leads to widespread use of non-prescription antimicrobials in household products. Triclocarban (3,4,4′-trichlorocarbanilide; TCC) is an antimicrobial compound added to bar soaps for its bacteriostatic properties. We previously demonstrated that TCC concentrates in and is transferred through the milk to suckling neonatal rats, potentially leading to alterations in the diversity of the gut microbiota. To date, the consequence of TCC exposure during early life on gut microbial composition is unknown.      

Timed-pregnant SD rats were provided ad lib access to TCC supplemented diet (0.1% w/w) starting at gestational day (GD) 4 until postnatal day (PND) 16 after birth. Fecal samples were collected from dams during gestation and lactation. Cecum content was collected from neonates during lactation only. A group of age-matched unexposed dams and their neonates served as controls. The V4 region of the 16S rRNA region was sequenced via the MiSeq platform.  Sequences were analyzed with the Phyloseq and Vegan packages in R.

Exposure to TCC during gestation and lactation led to perturbations in microbial community structure across time in both dams and neonates. Phylogenetic diversity was significantly reduced among exposed dams from GD 11 until sacrifice and neonates at PNDs 12 and 16. Weighted Unifrac analysis of microbiota from TCC exposed dams revealed significant dysbiosis of the gut microbiota by GD 18, a trend that continued to 16 days after delivery when the samples were last collected. Using the same metric among neonates, in both control and TCC exposed animals, an initial stochastic pattern emerges at PND 3. At PND 6, an overall restructuring occurs where both control and TCC exposed communities converge. By PND 12, communities start separating based on exposure status and become significantly different at PND 16.

Our results both demonstrate the impact of TCC exposure on gut microbial structure during gestation and lactation, as well as provide insight into the neonatal bacterial colonization process. The ability of TCC to drive microbial dysbiosis warrants future investigation to determine the clinical health outcomes resulting from non-prescription antimicrobial use during sensitive exposure windows.

Nothing to Disclose: RCK, RRF, MR, AMS, DB, JL, LZ, JC

*Please take note of The Endocrine Society's News Embargo Policy at https://www.endocrine.org/news-room/endo-annual-meeting/pr-resources-for-endo

Sources of Research Support: This study was supported by an NIEHS grant (1R21ES017475-01A1) and a UTK Professional Career Development Award.