176. Evaluation of the potential impact of a carbapenem de-escalation program at the Detroit Medical Center (DMC)
Session: Poster Abstract Session: Antibiotic Stewardship
Friday, October 21, 2011
Room: Poster Hall B1
Background: Group 2 carbapenem resistance in A .baumannii (AB), and P .aeruginosa (PA) poses a therapeutic challenge. Ertapenem is a Group 1 carbapenem with excellent in vitro activity against enterobacteriaceae, including ESBLs and ampC hyperproducers, but no appreciable activity against AB or PA. This narrower spectrum of activity provides an advantage in terms of selective antimicrobial pressure.  The objective of this study was to analyze Group 2 carbapenem usage in the DMC to identify potential ertapenem de-escalation opportunities.

Methods: Meropenem and imipenem usage at the DMC in 2009 was analyzed. The medical records of patients were analyzed to determine if de-escalation to ertapenem would have been appropriate.  Patients were considered to have been eligible for de-escalation if they were infected with a carbapenem-susceptible enterobacteriaceae, or if they had negative cultures and resided outside the ICU. Patients were not considered eligible if they received the Group 2 carbapenem for ≤ 72 hours or had cystic fibrosis, central nervous system infection, febrile neutropenia, infection due to Nocardia spp, or osteomyelitis.

Results: 599 patients were treated with meropenem or imipenem accounting for 3824 patient days of group 2 carbapenem utilization. The indications for carbapenem utilization were analyzed (Table). 176 (29%) of patients could have been de-escalated to ertapenem and 1074 (28%) patient days of Group II carbapenem utilization could have been avoided.  


A formalized carbapenem de-escalation program has the potential to significantly decrease group II carbapenem usage and decrease the selective antimicrobial pressure on AB and PA.

Table: Analysis of carbapenem utilization



Total patient days (n = 3824)

Total patients (n= 599)

Group II coverage warranted

Patient days (n=2232)

Patients (n=423)


AB or PA coverage needed

1152 (52%)


Cultures (-) ICU

483 (22%)


≤ 72 hours

451 (20%)


Cystic Fibrosis

48 (2%)


Central Nervous System Infection

40 (2%)



31 (1%)


Febrile Neutropenia

20 (1%)



7 (0.3%)


Ertapenem de-escalation opportunities

Patient days

(n = 1074)

Patients (n=176)


ESBL, ampC, or more susceptible organism

598 (56%)


Cultures (-) outside ICU

476 (44%)



Subject Category: A. Antimicrobial agents and Resistance

Jason Pogue, PharmD1, Dror Marchaim, MD1, Teena Chopra, MD2, Suchitha Bheemreddy, MBBS2, Jiha Lee3, Farah Ahmad, MD4, Aaisha Chaudry3 and Keith Kaye, MD, MPH, FIDSA1, (1)Detroit Medical Center (DMC) / Wayne State University, Detroit, MI, (2)Detroit Medical Center/Wayne State University, Detroit, MI, (3)Wayne State University, Detroit, MI, (4)Internal Medicine, Wayne State University, Detroit, MI


J. Pogue, Merck: Speaker's Bureau, Speaker honorarium

D. Marchaim, None

T. Chopra, None

S. Bheemreddy, None

J. Lee, None

F. Ahmad, None

A. Chaudry, None

K. Kaye, Merck: Grant Investigator and Speaker's Bureau, Research grant and Speaker honorarium

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.