title: Screening for nasal carriage of Staphylococcus aureus among patients scheduled to undergo orthopedic surgery: Incidence of surgical site infection by nasal carriage.
abstract: BACKGROUND
  Staphylococcus aureus (S. aureus), including MRSA, is considered to be the leading cause of surgical site infection (SSI) after orthopedic surgery. We screened for nasal carriers of S. aureus among patients who were scheduled to undergo orthopedic surgery at our hospital to reveal the effect of nasal S. aureus carriage on SSI. Our study design clearly has the intent of finding S. aureus nasal carriage and eradicating MRSA when found, and this strategy is to verify whether it's effective for preventing orthopedic surgical infections.
  
  
  METHODS
  Subjects were 4148 patients who underwent preoperative screening for nasal carrier and subsequently underwent orthopedic surgery during a 7-year period between April 2007 and March 2014. The incidence of SSI among patients who were operated in our department was investigated, and the rates were compared between patients with and without nasal carriage to reveal the effect of preoperative nasal carriage on SSI.
  
  
  RESULTS
  In total, 1036 patients were nasal carriers of S. aureus (carriage rate, 25.0%), whereas 140 patients carried MRSA (carriage rate, 3.4%). SSI developed in 24 patients [incidence, 0.58% (24/4148)] consisting of 12 non-carriers [0.39% (12/3112)] and 12 carriers [1.16% (12/1036)] with a significant difference in the incidence between the groups. Among 24 cases of SSI, more than half (13 cases) were caused by bacterial species other than S. aureus or those that could not be detected by the tests used. Only 7 patients out of 24 SSI patients, S. aureus was the bacterium detected in preoperative nasal cultures and the causal bacterium for SSI (concordance rate of 29.2%).
  
  
  CONCLUSIONS
  It was difficult to reduce the incidence rate of SSI in eradication group to the same level as nasal culture negative group. However, nasal carriage of S. aureus or MRSA may be a risk factor for SSI in orthopedic surgery.
authors.affiliation: Spine-Joint Reconstruction Centre, Tokushima Municipal Hospital, 2-34 Kita-Josanjima, Tokushima 770-0812, Japan. Electronic address: stnycky4714@mb.pikara.ne.jp.
authors.forename: Masaru
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Spine-Joint Reconstruction Centre, Tokushima Municipal Hospital, 2-34 Kita-Josanjima, Tokushima 770-0812, Japan.
authors.forename: Tateaki
authors.initials: T
authors.lastname: Shimakawa
authors.affiliation: Spine-Joint Reconstruction Centre, Tokushima Municipal Hospital, 2-34 Kita-Josanjima, Tokushima 770-0812, Japan.
authors.forename: Shunji
authors.initials: S
authors.lastname: Nakano
authors.affiliation: Spine-Joint Reconstruction Centre, Tokushima Municipal Hospital, 2-34 Kita-Josanjima, Tokushima 770-0812, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Chikawa
authors.affiliation: Spine-Joint Reconstruction Centre, Tokushima Municipal Hospital, 2-34 Kita-Josanjima, Tokushima 770-0812, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Yoshioka
authors.affiliation: Spine-Joint Reconstruction Centre, Tokushima Municipal Hospital, 2-34 Kita-Josanjima, Tokushima 770-0812, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kashima
authors.affiliation: Spine-Joint Reconstruction Centre, Tokushima Municipal Hospital, 2-34 Kita-Josanjima, Tokushima 770-0812, Japan.
authors.forename: Shunichi
authors.initials: S
authors.lastname: Toki
authors.affiliation: Department of Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-5 Kuramoto, Tokushima 770-8503, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Sairyo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002353:Carrier State / Q000382:microbiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009296:Nasal Cavity / Q000382:microbiology*; D019637:Orthopedic Procedures / Q000009:adverse effects*; D013203:Staphylococcal Infections / Q000175:diagnosis / Q000453:epidemiology*; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D013530:Surgical Wound Infection / Q000453:epidemiology* / Q000382:microbiology