Program Schedule

Compliance with follow-up cultures in Staphylococcus aureus bacteremia: Opportunity for quality improvement

Session: Oral Abstract Session: Respiratory and Staphylococcal Infections
Thursday, October 9, 2014: 11:30 AM
Room: The Pennsylvania Convention Center: 105-AB
Background: Treatment failure in uncomplicated Staphylococcus aureus bacteremia (SAB) occurs in 20-30% of cases. Published guidelines recommend follow-up blood cultures (cx) to document clearance of SAB within 72 hrs of treatment initiation. We hypothesized that not all patients (pts) with SAB would have follow-up blood cultures done and that pts without documented clearance would have higher in-hospital mortality.

Methods: We performed a retrospective cohort study of adult pts with their first episode of SAB from 2008-2012 at a large academic medical center. Pts were excluded if they left AMA, were discharged to hospice, or had a blood cx’s obtained ≤72 hours from discharge or death. We used logistic regression to study the association between SAB clearance (≥1 negative cx collected >1 hour after the last positive cx) and mortality. We estimated the causal risk difference of documenting SAB clearance versus failure to do so using the g-computation approach.

Results: We identified 1,437 pts with SAB; 873 pts met study inclusion criteria. Study pts median age = 57 (IQR: 46-67) yrs, were predominantly male (60.1%, n=525), Caucasian (60.1%, n=525) and the median Charlson score = 2.0 (IQR: 1.0-5.0). The median length of stay = 14.0 (8.0-25.0) days and 48.8% (n=426) had an ICU admission. 88.4% of SAB were healthcare-associated. 45.0% (n=393) of pts had a central venous catheter. 33.1% (n=289) were hemodialysis pts, 11.1% (n=97) had endocarditis and 6.4% (n=56) had pneumonia. The mean duration of SAB = 1.1 (±4.6) days and duration of antibiotics = 10.2 (±12.5) days. Failure to perform follow-up cx to confirm clearance occurred in 11.5% (n=100) of pts. In-hospital mortality was greater in pts without documented clearance [27/100 (27%) w/o vs. 67/773 (8.7%) w/ clearance]. Failure to document SAB clearance (OR = 5.4, 95% CI: 2.7, 10.0), Charlson comorbidity score (OR = 1.3, 95% CI: 1.1, 1.4), ICU admission (OR = 8.1, 95% CI: 4.2, 15.7) and pneumonia (OR = 2.6, 95% CI: 1.1, 5.9) were independent predictors of mortality. The estimated causal risk difference of mortality per 100 SAB pts without documented clearance was 18.9% (95% CI: 17.4%, 20.5%) compared to those with documented clearance.

Conclusion: A lack of repeat cultures to document clearance of SAB occurred in 11.5% of pts and was independently associated with poor outcomes.

Benjamin S. Thomas, M.D.1, S. Reza Jafarzadeh, PhD1, Jonas Marschall, M.D.1,2, Victoria J. Fraser, MD, FIDSA, FSHEA1 and David K. Warren, MD, MPH, FIDSA, FSHEA1, (1)Division of Infectious Diseases, Washington University School of Medicine, St. Louis, MO, (2)Department of Infectious Diseases and Hospital Epidemiology, University Hospital Bern, Bern, Switzerland


B. S. Thomas, None

S. R. Jafarzadeh, None

J. Marschall, None

V. J. Fraser, None

D. K. Warren, None

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