Association between vancomycin-resistant Enterococci bacteremia and ceftriaxone usage.
OBJECTIVE
Vancomycin-resistant enterococci (VRE) have become a public health concern with implications for patient mortality and costs. Hospital antibiotic usage may impact VRE incidence, but the relationship is poorly understood. Animal investigations suggest that ceftriaxone may be associated with VRE proliferation. We measured antimicrobial usage and VRE bloodstream infection (VRE-BSI) incidence to test our hypothesis that increased ceftriaxone usage would be associated with a higher incidence of VRE-BSI.


METHODS
Retrospective cohort study.


METHODS
University of Alabama at Birmingham Medical Center, a 900-bed urban tertiary care hospital.


METHODS
All patients admitted during the study period contributed data.


METHODS
We conducted a retrospective analysis of antimicrobial usage and VRE-BSI from 2005 to 2008 (43 months). Antimicrobial usage was quantified as days of therapy (DOTs) per 1,000 patient-days. VRE-BSI incidence was calculated as cases per 1,000 patient-days. Negative binomial regression with adjustment for correlation between consecutive observations was used to measure the association between antimicrobial usage and VRE-BSI incidence at the hospital- and care-unit levels.


RESULTS
VRE-BSI incidence increased from 0.06 to 0.17 infections per 1,000 patient-days. Hospital VRE-BSI incidence was associated with prior-month ceftriaxone DOTs (incidence rate ratio, 1.38 per 10 DOTs; P = .005). After controlling for ceftriaxone, prior-month cephalosporin usage (class) was not predictive of VRE-BSI (P = .70). Similarly, prior-month usage of piperacillin-tazobactam, ceftazidime, cefepime, cefazolin, or vancomycin was not predictive of VRE-BSI when considered individually (P≥ .4 for all comparisons). The final model suggests that type of intensive care unit was related to VRE-BSI incidence.


CONCLUSIONS
Ceftriaxone usage in the prior month, but not cephalosporin (class) or vancomycin usage, was related to VRE-BSI incidence. These findings suggest that an antimicrobial stewardship program that limits ceftriaxone may reduce nosocomial VRE-BSI incidence.
Infectious Disease Clinical Outcomes Research Unit, Division of Infectious Disease, Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, 1124 West Carson Street, Torrance, CA 90502, USA. Dr.McKinnell@yahoo.com
James A
JA
McKinnell
Danielle F
DF
Kunz
Eric
E
Chamot
Mukesh
M
Patel
Rhett M
RM
Shirley
Stephen A
SA
Moser
John W
JW
Baddley
Peter G
PG
Pappas
Loren G
LG
Miller
D000407:Alabama; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002443:Ceftriaxone / Q000627:therapeutic use*; D000075202:Contraindications; D003428:Cross Infection / Q000188:drug therapy*; D016983:Enterococcus / Q000187:drug effects*; D005260:Female; D006786:Hospitals, Urban; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014640:Vancomycin / Q000627:therapeutic use*; D020713:Vancomycin Resistance / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D014640:Vancomycin; D002443:Ceftriaxone