title: Trends in incidence and susceptibility among methicillin-resistant Staphylococcus aureus isolated from intranasal cultures associated with rhinosinusitis.
abstract: BACKGROUND
  Reports regarding the incidence and antibiotic susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) in rhinosinusitis (RS) are limited. This study was designed to identify epidemiology and trends of MRSA incidence and antimicrobial resistance in the sinonasal cavities.
  
  
  METHODS
  This is a retrospective case series. All intranasal/sinus cultures obtained by otolaryngologists at Stanford over a 20-year period (1990-2010) were retrospectively reviewed by mining the microbiology database. Nested searches were then made for all S. aureus and MRSA cultures. Patterns of incidence and changes in antibiotic susceptibilities were tabulated and statistical analysis was performed.
  
  
  RESULTS
  Our search retrieved 10,387 positive intranasal culture samples, with S. aureus found in 800 (7.7%), and MRSA comprising 110 (1.06%) of this subset. Between the years of 1990 and 1999, only 2/112 (1.7%) of S. aureus-positive nasal cultures were positive for MRSA, with a sharp rise in incidence to 86/606 (14.2%) from 2000 to 2005, and to 22/82, 26.8% from 2006 to 2010. On a percent basis, using logistic regression modeling, this represents a statistically significant increasing trend (p < 0.0001) for MRSA sinusitis. However, over the 20-year interval studied, the patterns of antibiotic resistance among MRSA remained unaltered, especially with regard to trimethoprim-sulfamethoxazole and vancomycin.
  
  
  CONCLUSIONS
  S. aureus and MRSA isolates from intranasal cultures, which were essentially absent before the year 2000, became significantly more common earlier this decade. These data show the increased role of MRSA in sinusitis. MRSA antibiotic susceptibilities have remained, however, largely stable during this time period.
authors.affiliation: Department of Otolaryngology, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Valin
authors.initials: V
authors.lastname: Rujanavej
authors.forename: Ethan
authors.initials: E
authors.lastname: Soudry
authors.forename: Niaz
authors.initials: N
authors.lastname: Banaei
authors.forename: Ellen Jo
authors.initials: EJ
authors.lastname: Baron
authors.forename: Peter H
authors.initials: PH
authors.lastname: Hwang
authors.forename: Jayakar V
authors.initials: JV
authors.lastname: Nayak
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000009:adverse effects; D002140:California / Q000453:epidemiology; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification / Q000472:pathogenicity; D008875:Middle Aged; D009296:Nasal Cavity / Q000187:drug effects / Q000382:microbiology; D010256:Paranasal Sinuses / Q000187:drug effects / Q000382:microbiology; D012189:Retrospective Studies; D012220:Rhinitis / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D012852:Sinusitis / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D013203:Staphylococcal Infections / Q000150:complications* / Q000188:drug therapy / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents
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