Comparison of unit-specific and hospital-wide antibiograms: potential implications for selection of empirical antimicrobial therapy.
OBJECTIVE
To identify differences between unit-specific and hospital-wide antibiograms and to determine the potential impact of these differences on selection of empirical antimicrobial therapy.


METHODS
A 625-bed tertiary care medical center.


METHODS
Antimicrobial susceptibility results were collected for all inpatient clinical bacterial isolates recovered over a 3-year period; isolates were categorized by the hospital location of the patient at the time of sampling and by the anatomic site from which the isolate was recovered. Antibiograms from each unit were compiled for the most commonly isolated organisms and were compared to the hospital-wide antibiogram.


RESULTS
A total of 9,970 bacterial isolates were evaluated in this study, including 2,646 enterococcal isolates, 2,806 S. aureus isolates, 2,795 E. coli isolates, and 1,723 Pseudomonas aeruginosa isolates. The percentages of bacterial isolates resistant to antimicrobials were significantly higher in the medical ICU and surgical ICU than the hospital-wide antibiogram would have predicted, whereas the percentages of isolates susceptible to antimicrobials were significantly higher in the non-ICU units, compared with the hospital overall. However, on general medicine units, the prevalence of susceptibility to levofloxacin was significantly lower than that for the hospital overall.


CONCLUSIONS
Unit-specific antibiograms are important for making informed decisions about empirical antimicrobial therapy, because the hospital-wide antibiogram may mask important differences in susceptibility rates across different units. These differences may have important implications for selecting the optimal empirical antimicrobial therapy.
Binkley
Shawn
S
Division of Infectious Diseases, Department of Pharmacy, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
Fishman
Neil O
NO
LaRosa
Lori A
LA
Marr
Ann Marie
AM
Nachamkin
Irving
I
Wordell
David
D
Bilker
Warren B
WB
Lautenbach
Ebbing
E
D000890:Anti-Infective Agents / Q000008:administration & dosage*; D019072:Antibiotic Prophylaxis; D001419:Bacteria / Q000145:classification / Q000302:isolation & purification; D006757:Hospital Units; D008826:Microbial Sensitivity Tests; D013045:Species Specificity
D000890:Anti-Infective Agents