82. Comparison of a hospital-cumulative antibiogram with patient characteristic-stratified web-based antibiogram
Session: Oral Abstract Session: PIDS Featured Abstracts
Thursday, October 8, 2015: 10:30 AM
Room: 6--CF
Background: The selection of empirical antimicrobial therapy is often based on susceptibility rates from a composite antibiogram. Unfortunately, institution-wide antibiograms could mask important differences in susceptibility data within specific patient subsets, such as age, culture source, setting of acquisition, or clinical syndrome. Thus, stratifying antibiograms by these factors might help clinicians better target empiric antimicrobial therapy.  

Methods: We developed a prevalence-weighted, condition-specific, real-time antibiogram that aggregates and displays bacterial culture data from our electronic health record according to Clinical and Laboratory Standards Institute guidelines. Using a commercial data visualization platform (Qlikview) that can be refreshed periodically to incorporate new information, we compared susceptibility rates for selected pathogen-drug-patient combinations between the cumulative and stratified antibiograms using χ2 or Fisher’s exact test.

Results: The stratified antibiogram revealed important differences in antimicrobial susceptibility across epidemiologic subsets of patients. For example, the overall susceptibility of methicillin-resistant S. aureus (MRSA) to clindamycin was 78%, but was 91% from wound cultures obtained in the Emergency Department [c2 (1, N=3425) =74.7, p <0.01]. Similarly, the susceptibility of E. coli to cefazolin among all urine cultures was 87% compared with 67% in hospital-onset urinary tract infections [c2 (1, N=2754) =53.1, p <0.01]. The web-based antibiogram also displayed real time information regarding the most common organisms isolated, with important differences when stratified by hospital unit. For example, Staphylococcus aureus accounted for 21% of community-onset (<48 h from admission) bacteremia but only 6% of pathogens among oncology patients with bacteremia.

Conclusion: Stratified antibiograms reveal clinically important differences in susceptibility patterns that can be obscured by hospital-cumulative antibiograms. Further research is needed to determine if delivery of this information to front line clinicians can facilitate appropriate antibiotic selection.

Beatriz Larru, MD, PhD1, Luis Ahumada, MSCS2, Talene A. Metjian, PharmD3, Kaede Ota, MD4, Bimal Desai, MD, MBI1, Theoklis Zaoutis, MD, MSCE, FPIDS5 and Jeffrey S. Gerber, MD, PhD6, (1)Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, (2)Information Services, The Children's Hospital of Philadelphia, Philadelphia, PA, (3)Antimicrobial Stewardship Program, The Children's Hospital of Philadelphia, Philadelphia, PA, (4)Pathology & Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, (5)Division of Infectious Diseases, Center for Pediatric Clinical Effectiveness, the Children's Hospital of Philadelphia, Philadelphia, PA, The Children's Hospital of Philadelphia, Philadelphia, PA, (6)Department of Pediatrics, Division of Infectious Diseases, The Children's Hospital of Philadelphia, Philadelphia, PA


B. Larru, None

L. Ahumada, None

T. A. Metjian, None

K. Ota, None

B. Desai, None

T. Zaoutis, Merck: Grant Investigator , Research grant

J. S. Gerber, None

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