title: Incidence of methicillin-resistant Staphylococcus aureus causing chronic rhinosinusitis.
abstract: OBJECTIVE
  To identify the incidence of methicillin-resistant Staphylococcus aureus (MRSA) causing chronic rhinosinusitis (CRS) and identify whether antibiotic use and previous endoscopic sinus surgeries (ESS) contribute to its development.
  
  
  METHODS
  A retrospective case control analysis, with the control group randomly selected and matched for age and sex.
  
  
  METHODS
  All patients undergoing an endonasal culture in a tertiary otolaryngology center between April 2001 and March 2003 for mucopurulent rhinosinusitis were identified. A chart review was undertaken to identify those patients with a positive MRSA culture result. An age- and sex-matched control group was randomly chosen, and an interview was conducted to identify antibiotic use and previous ESS. A statistical analysis on these two variables was carried out using a t test and the Wilcoxon rank-sum test.
  
  
  RESULTS
  Two hundred eighty cultures were identified in 188 patients, and of these, 264 cultures in 173 patients met the inclusion criteria. There were 141 positive cultures and 13 positive MRSA cultures. The overall incidence of MRSA in this population was 9.22%. The mean number of antibiotic courses in the MRSA and the control groups was 33.2 and 26.7, respectively, which was not statistically significant (P =.43). The 95% confidence interval (CI) for this mean difference of 6.5 is -9.8 to 22.8. The mean number of ESS in the MRSA and control groups was 2.0 and 1.9, respectively, which was not statistically significant (P =.93). The 95% CI for this mean difference of 0.06 is -1.3 to 1.4.
  
  
  CONCLUSIONS
  We identified a 9.22% incidence of MRSA-causing CRS. The frequency of antibiotic use and previous ESS were found not to be statistically significant causes of MRSA sinusitis. However, the 95% CI for antibiotic usage is skewed to the right, indicating a possible role for its contribution to the emergence of MRSA-causing CRS.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, New York Presbyterian Hospital-Weill Cornell Center, Joan and Sanford Weill Medical College of Cornell University, New York, NY, USA.
authors.forename: Casey R A
authors.initials: CR
authors.lastname: Manarey
authors.forename: Vijay K
authors.initials: VK
authors.lastname: Anand
authors.forename: Clark
authors.initials: C
authors.lastname: Huang
mesh_terms: D000328:Adult; D002908:Chronic Disease; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D016106:Methicillin Resistance; D012189:Retrospective Studies; D012220:Rhinitis / Q000382:microbiology*; D012852:Sinusitis / Q000382:microbiology*; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*