title: Surgical site infections in spine surgery: identification of microbiologic and surgical characteristics in 239 cases.
abstract: METHODS
  Retrospective analysis.
  
  
  OBJECTIVE
  The objective of this study was to describe the microbiology of surgical site infection (SSI) in spine surgery and relationship with surgical management characteristics.
  
  
  BACKGROUND
  SSI is an important complication of spine surgery that results in significant morbidity. A comprehensive and contemporary understanding of the microbiology of postoperative spine infections is valuable to direct empiric antimicrobial treatment and prophylaxis and other infection prevention strategies.
  
  
  METHODS
  All cases of spinal surgery associated with SSI between July 2005 and November 2010 were identified by the hospital infection control surveillance program using Centers for Disease Control National Health Safety Network criteria. Surgical characteristics and microbiologic data for each case were gathered by direct medical record review.
  
  
  RESULTS
  Of 7529 operative spine cases performed between July 2005 and November 2010, 239 cases of SSI were identified. The most commonly isolated pathogen was Staphylococcus aureus (45.2%), followed by Staphylococcus epidermidis (31.4%). Methicillin-resistant organisms accounted for 34.3% of all SSIs and were more common in revision than in primary surgical procedures (47.4% vs. 28.0%, P = 0.003). Gram-negative organisms were identified in 30.5% of the cases. Spine surgical procedures involving the sacrum were significantly associated with gram-negative organisms (P < 0.001) and polymicrobial infections (P = 0.020). Infections due to gram-negative organisms (P = 0.002) and Enterococcus spp. (P = 0.038) were less common in surgical procedures involving the cervical spine. Cefazolin-resistant gram-negative organisms accounted for 61.6% of all gram-negative infections and 18.8% of all SSIs.
  
  
  CONCLUSIONS
  Although gram-positive organisms predominated, gram-negative organisms accounted for a sizeable portion of SSI, particularly among lower lumbar and sacral spine surgical procedures. Nearly half of infections in revision surgery were due to a methicillin-resistant organism. These findings may help guide choice of empiric antibiotics while awaiting culture data and antimicrobial prophylaxis strategies in specific spine surgical procedures.
  
  
  METHODS
  3.
authors.affiliation: *Department of Orthopedic Surgery, Louisiana State University Health Sciences Center, New Orleans, LA; Departments of †Orthopedic Surgery and ‡Neurological Surgery, University of California, San Francisco Medical Center, San Francisco, CA; and §Department of Medicine, Division of Infectious Diseases, University of California, San Francisco, CA.
authors.forename: Amir
authors.initials: A
authors.lastname: Abdul-Jabbar
authors.forename: Sigurd H
authors.initials: SH
authors.lastname: Berven
authors.forename: Serena S
authors.initials: SS
authors.lastname: Hu
authors.forename: Dean
authors.initials: D
authors.lastname: Chou
authors.forename: Praveen V
authors.initials: PV
authors.lastname: Mummaneni
authors.forename: Steven
authors.initials: S
authors.lastname: Takemoto
authors.forename: Christopher
authors.initials: C
authors.lastname: Ames
authors.forename: Vedat
authors.initials: V
authors.lastname: Deviren
authors.forename: Bobby
authors.initials: B
authors.lastname: Tay
authors.forename: Phil
authors.initials: P
authors.lastname: Weinstein
authors.forename: Shane
authors.initials: S
authors.lastname: Burch
authors.forename: Catherine
authors.initials: C
authors.lastname: Liu
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D019072:Antibiotic Prophylaxis / Q000379:methods; D001424:Bacterial Infections / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology*; D016983:Enterococcus / Q000187:drug effects / Q000302:isolation & purification; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000302:isolation & purification; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000302:isolation & purification; D006801:Humans; D008712:Methicillin / Q000627:therapeutic use; D016106:Methicillin Resistance; D019637:Orthopedic Procedures / Q000379:methods*; D012189:Retrospective Studies; D013131:Spine / Q000601:surgery*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification; D013212:Staphylococcus epidermidis / Q000187:drug effects / Q000302:isolation & purification; D013530:Surgical Wound Infection / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D008712:Methicillin