title: Investigation of bacterial repopulation after sinus surgery and perioperative antibiotics.
abstract: 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 examined changes in the sinus microbiome after ESS and medical 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 sampled 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 anterior nares and ethmoid at surgery (M-H = 0.58 and 0.59, respectively), and were least similar to the nasopharynx (M-H = 0.28). Principal coordinates analysis (PCoA) plots illustrate that the ethmoid microbiota temporarily shifted after surgery and antibiotics but returned toward baseline in many subjects.
  
  
  CONCLUSIONS
  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 antibiotic therapy does not appear to reduce bacterial burden, but rather, shifts the microbial consortia.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Colorado, Boulder, CO.
authors.forename: Leah J
authors.initials: LJ
authors.lastname: Hauser
authors.affiliation: Division of Infectious Diseases, University of Colorado, Boulder, CO.
authors.forename: Diana
authors.initials: D
authors.lastname: Ir
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Colorado, Boulder, CO.
authors.forename: Todd T
authors.initials: TT
authors.lastname: Kingdom
authors.affiliation: The Microbiome Research Consortium, University of Colorado, Aurora, CO.|Department of Biostatistics and Informatics, University of Colorado, Boulder, CO.|Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Robertson
authors.affiliation: Division of Infectious Diseases, University of Colorado, Boulder, CO.|The Microbiome Research Consortium, University of Colorado, Aurora, CO.
authors.forename: Daniel N
authors.initials: DN
authors.lastname: Frank
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Colorado, Boulder, CO.
authors.forename: Vijay R
authors.initials: VR
authors.lastname: Ramakrishnan
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D019072:Antibiotic Prophylaxis / Q000009:adverse effects; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D004724:Endoscopy; D005005:Ethmoid Sinus / Q000382:microbiology*; D005260:Female; D006801:Humans; D008297:Male; D064307:Microbiota; D008875:Middle Aged; D009305:Nasopharynx / Q000382:microbiology*; D019990:Perioperative Care / Q000009:adverse effects / Q000379:methods; D012220:Rhinitis / Q000382:microbiology / Q000601:surgery*; D012852:Sinusitis / Q000382:microbiology / Q000601:surgery*; D013530:Surgical Wound Infection / Q000517:prevention & control; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents
keywords: bacteria; bacterial repopulation; chronic rhinosinusitis; microbiome; pyrosequencing; sinusitis