title: The impact of prebiopsy antibiotics on pathogen recovery in hematogenous vertebral osteomyelitis.
abstract: BACKGROUND
  Biopsy specimens are often obtained in the evaluation of hematogenous vertebral osteomyelitis. The effect of prebiopsy antibiotic exposure on pathogen recovery is unknown.
  
  
  METHODS
  We conducted a retrospective cohort study of adult inpatients with hematogenous vertebral osteomyelitis at a tertiary care hospital from 1 January 2003 through 31 July 2007. Antibiotic exposure within 14 days before biopsy was evaluated.
  
  
  RESULTS
  Of 150 patients with hematogenous vertebral osteomyelitis, 92 (61%) underwent a biopsy (60 [65%] needle and 32 [35%] open biopsies). The median time from admission to biopsy was 3 days (range, 0-69 days). Patients who underwent biopsy were more likely to have weakness (53 [58%] biopsy vs 15 [26%] no biopsy; P<.001) and sensory loss (27 [29%] vs 6 [10%]; P=.006), but were less likely to have a positive blood culture result (28 [30%] vs 30 [52%]; P=.01). Pathogens were recovered in 61 patients (66%). Open biopsy had a higher yield than needle biopsy (29 [91%] of 32 vs 32 [53%] of 60; P<.001). Sixty patients (65%) who had biopsies performed received antibiotics ≤14 days before the procedure (median duration, 4 days; range, 1-37 days). Open biopsy predicted positive biopsy culture results (adjusted odds ratio, 8.4; 95% confidence interval, 2.2-31.8), but there was no association of prebiopsy antibiotics with culture results (adjusted odds ratio, 2.3; 95% confidence interval, 0.8-6.2).
  
  
  CONCLUSIONS
  A pathogen was recovered from 61 (66%) of 92 patients who had biopsies performed in this cohort of hematogenous vertebral osteomyelitis. Open biopsies had a higher microbiological yield than did needle biopsies. Antibiotic exposure before biopsy did not negatively impact pathogen recovery and should not be the sole reason for foregoing biopsies.
authors.affiliation: Division of Infectious Diseases, Washington University School of Medicine, St Louis, Missouri 63110, USA. jmarscha@dom.wustl.edu
authors.forename: Jonas
authors.initials: J
authors.lastname: Marschall
authors.forename: Kavita P
authors.initials: KP
authors.lastname: Bhavan
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Olsen
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: Fraser
authors.forename: Neill M
authors.initials: NM
authors.lastname: Wright
authors.forename: David K
authors.initials: DK
authors.lastname: Warren
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D001419:Bacteria / Q000302:isolation & purification*; D001706:Biopsy / Q000379:methods; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010019:Osteomyelitis / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology; D012189:Retrospective Studies; D013122:Spinal Diseases / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents