564. Prior Antimicrobial Therapy as a Risk Factor for Culture Negative Prosthetic Joint Infection: A Case-Control Study
Session: Poster Session: Hospital-acquired and Transplant Infections
Friday, October 30, 2009: 12:00 AM
Room: Poster Hall A
Background: Risk factors and outcome for culture negative (CN) prosthetic joint infection (PJI) have not been well studied. We performed a retrospective case-control study in order to define demographics, risk factors, and the outcome of patients with CN PJI.
Methods: All case patients with CN PJI were evaluated at our institution between January 1, 1985 and December 31, 2000. Controls were patients with culture positive PJI that were matched to cases based on the diagnosis date and site of infected joint.
Results: We identified 135 case patients with CN PJIs and 135 controls with culture positive PJI’s during the study period. A course of antimicrobial therapy whithin three month prior to the diagnosis PJI was used in 64% of case patients (87/135) and 25% (34/135) of controls. Forty two percent (56/135) case patients and fifty percent (67/135) of controls were treated with staged surgical therapy. The median length of parenteral antimicrobial therapy was 22 days (range 0-136 days) for case patients and 28 days (0-95) for controls. The most commonly used parenteral antimicrobial in case patients with CN PJI was cefazolin 69% (88/128) followed by vancomycin 13% (17/128). The percent (SE) cumulative incidence free of treatment failure at 2 years of follow up was 75% (±4%) and 79%(±3.7%) for cases and controls, respectively (P value=0.2). In a multivariable analysis the use of prior antimicrobial therapy and post operative wound drainage following index arthroplasty were associated with an increased odds of being CN PJI (OR=4.7; 95% CI: 2.8-8.1 and OR=3.5; 95% CI: 1.5-8.1 respectively).
Conclusion: Prior antimicrobial therapy and post operative wound drainage were associated with an increased risk of CN PJI. Physicians should critically evaluate the need for antimicrobial therapy prior to establishing a microbiologic diagnosis of PJI in PJI suspect patients
Elie Berbari, MD1, Arlen Hanssen, MD2, Brian Lahr, MS2, Davud Malekzadeh,, can med53, Duffy Mary, RN2, Douglas Osmon, MD4, Jeanette Passow, PhD2, Robin Patel, MD, FIDSA2, Irene Sia, MD2, James Steckelberg, MD, FIDSA5 and  D. Malekzadeh,, None..
D. Osmon, None..
B. Lahr, None..
A. Hanssen, None..
R. Patel, None..
J. Passow, None..
I. Sia, None..
D. Mary, None..
J. Steckelberg, None..
E. F. Berbari, None., (1)Division of Infectious Diseases, Mayo Clinic, Rochester, MN, (2)Mayo Clinic, Rochester, MN, (3)5Paracelsus Medical Privatuniversity ., Rochester, MN, (4)Infectious Diseases/Internal Medicine, Mayo Clinic, Rochester, MN, (5)Department of Medicine, Division of Infectious Diseases, Mayo Clinic, Rochester, MN

Disclosures:

E. Berbari, None

A. Hanssen, None

B. Lahr, None

D. Malekzadeh,, None

D. Mary, None

D. Osmon, None

J. Passow, None

R. Patel, None

I. Sia, None

J. Steckelberg, None