2016 Section 5 Green Book

Reprinted by permission of Int Forum Allergy Rhinol. 2015; 6(11):34-40.

OR I G I NAL ART I CLE

Investigation of bacterial repopulation a er sinus surgery and perioperative antibiotics Leah J. Hauser, MD 1 , Diana Ir, BS 2 , Todd T. Kingdom, MD 1 , Charles E. Robertson, PhD 3,4,5 , Daniel N. Frank, PhD 2,3 and Vijay R. Ramakrishnan, MD 1

Background: Endoscopic sinus surgery (ESS) enjoys high success rates, but repopulation with pathogenic bacteria is 1 of the hallmarks of poorer outcomes. There are many hypothesized sources of repopulating bacteria; however, this process remains largely unexplored. This study exam- ined changes in the sinus microbiome a er ESS and medi- cal therapies to identify potential sources for postsurgical microbial repopulation. Methods: Samples from the anterior nares, ethmoid sinus, and nasopharynx were taken at the time of surgery from 13 subjects undergoing ESS for chronic rhinosinusitis (CRS). Patients were treated postoperatively with 2 weeks of oral antibiotics and saline rinses. The ethmoid sinus was sam- pled at 2 and 6 weeks postoperatively; microbiota were characterized using quantitative polymerase chain reaction (qPCR) and 16S ribosomal RNA (rRNA) gene sequencing. The Morisita-Horn beta-diversity index (M-H) was used to compare similarity between samples. Results: The bacterial burden of the ethmoid was higher 2 weeks postoperatively than 6 weeks postoperatively ( p = 0.01). The 6-week samples most closely represented the an- terior nares and ethmoid at surgery (M-H = 0.58 and 0.59, 1 Department of Otolaryngology–Head and Neck Surgery, University of Colorado, Boulder, CO; 2 Division of Infectious Diseases, University of Colorado, Boulder, CO; 3 The Microbiome Research Consortium, University of Colorado, Aurora, CO; 4 Department of Biostatistics and Informatics, University of Colorado, Boulder, CO; 5 Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO Correspondence to: Vijay R. Ramakrishnan, MD, Department of Otolaryngology–Head and Neck Surgery, University of Colorado, 12631 E. 17th Ave, B-205, Boulder, CO 80045; e-mail: vijay.ramakrishnan@ucdenver.edu Funding sources for the study: NeilMed Pharmaceuticals; University of Colorado, Department of Otolaryngology. Potential conflict of interest: None provided. Presented to the ARS at the Combined Otolaryngology Spring Meetings (COSM) on April 24, 2015, in Boston, MA. Received: 1 April 2015; Revised: 10 July 2015; Accepted: 21 July 2015

respectively), and were least similar to the nasopharynx (M- H = 0.28). Principal coordinates analysis (PCoA) plots illus- trate that the ethmoid microbiota temporarily shi ed af- ter surgery and antibiotics but returned toward baseline in many subjects. Conclusion: Bacterial communities colonizing the ethmoid 6 weeks postoperatively were most similar to anterior nasal cavity and pretreatment sinus microbial profiles, indicating a high degree of resilience in the sinonasal microbiome of most subjects. Interestingly, surgery and postoperative an- tibiotic therapy does not appear to reduce bacterial bur- den, but rather, shi s the microbial consortia. C 2015 ARS- AAOA, LLC. Key Words: sinusitis; chronic rhinosinusitis; bacteria; microbiome; py- rosequencing; bacterial repopulation How to Cite this Article : Hauser LJ, Ir D, Kingdom TT, Robertson CE, Frank DN, Ra- makrishnan VR. Investigation of bacterial repopulation af- ter sinus surgery and perioperative antibiotics. Int Forum Allergy Rhinol. 2016;6:34–40. C hronic rhinosinusitis (CRS) is a chronic inflammatory disorder of the paranasal sinuses, in which bacteria may play some role. 1 Surgical therapy and medical treat- ment in the early postoperative period are directed at im- proving sinus ventilation, eradicating pathogenic bacteria, and perhaps restoring microbiome disturbances to a healthy state. Although 72% to 90% of patients have good post- operative outcomes, 2–5 a subset of patients have continued disease requiring further medical and surgical therapy. Repopulation with pathogenic bacteria is 1 of the hall- marks of a poor outcome after endoscopic sinus surgery (ESS). 6,7 Many theories have been proposed for the source of bacterial repopulation, including persistence of bacterial

DOI: 10.1002/alr.21630 View this article online at wileyonlinelibrary.com.

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