2016 Section 5 Green Book

Bacterial repopulation after surgery & antibiotics

FIGURE 4. PCoA of microbial communities. PCoA was performed on genus-level microbiome data using Morisita-Horn similarity scores calculated on each pair of samples. The top 3 plots show the distribution of samples along PC1-PC2, PC1-PC3, and PC2-PC3. Baseline, 2-week, and 6-week samples are designated by circles, squares, and triangles, respectively. Each subject is designated by a unique color. The bottom 12 plots display the PC1-PC2 plots for individual subjects. ESS = endoscopic sinus surgery; PCoA = principal coordinates analysis.

complex interplay between the microbiome and therapeu- tic interventions.

resilience of these sites and suggesting they may be poten- tial sources for repopulation of bacteria postoperatively. Bacterial communities appear to largely return to their nor- mal preoperative state, with some degree of interpersonal variation, identifying another variable that could affect therapeutic outcomes. Interestingly, postoperative antibi- otic therapy did not reduce the bacterial burden, but rather shifted the microbial consortia.

Conclusion Bacterial communities colonizing the ethmoid at 6 weeks postoperatively were most similar to anterior nasal cavity and pretreatment sinus microbial profiles, indicating the

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3. Lund, VJ. Evidence-based surgery in chronic rhinosi- nusitis. Acta Otolaryngol . 2001;121:5–9. 4. Kennedy, DW. Prognostic factors, outcomes and staging in ethmoid sinus surgery. Laryngoscope . 1992;102:1–18. 5. Smith, TL, Litvack, JR, Hwang, PH, et al. Determinants of outcomes of sinus surgery: a

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