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2006
Surveillance for vancomycin-resistant enterococci: Type, rates, Surveillance for vancomycin-resistant enterococci: Type, rates,
costs, and implications costs, and implications
Brooke N. Shadel
Saint Louis University, School of Public Health
Laura A. Puzniak
Saint Louis University, School of Public Health
Kathleen N. Gillespie
Saint Louis University, School of Public Health
Steven J. Lawrence
Washington University School of Medicine in St. Louis
Marin Kollef
Washington University School of Medicine in St. Louis
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Recommended Citation Recommended Citation
Shadel, Brooke N.; Puzniak, Laura A.; Gillespie, Kathleen N.; Lawrence, Steven J.; Kollef, Marin; and Mundy,
Linda M., ,"Surveillance for vancomycin-resistant enterococci: Type, rates, costs, and implications."
Infection Control and Hospital Epidemiology. 27,10. 1068-1075. (2006).
https://digitalcommons.wustl.edu/open_access_pubs/914
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Surveillance for Vancomycin‐Resistant Enterococci: Type, Rates, Costs, and Implications•
Author(s): BrookeN. Shadel , PhD, MPH, LauraA. Puzniak , PhD, MPH, KathleenN.
Gillespie , PhD, StevenJ. Lawrence , MD, Marin Kollef , MD, LindaM. Mundy , MD
Reviewed work(s):
Source:
Infection Control and Hospital Epidemiology,
Vol. 27, No. 10 (October 2006), pp. 1068-
1075
Published by: The University of Chicago Press on behalf of The Society for Healthcare Epidemiology of
America
Stable URL: http://www.jstor.org/stable/10.1086/507960 .
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infection control and hospital epidemiology october 2006, vol. 27, no. 10
original article
Surveillance for Vancomycin-Resistant Enterococci:
Type, Rates, Costs, and Implications
Brooke N. Shadel, PhD, MPH; Laura A. Puzniak, PhD, MPH; Kathleen N. Gillespie, PhD; Steven J. Lawrence, MD;
Marin Kollef, MD; Linda M. Mundy, MD
objective. To evaluate 2 active surveillance strategies for detection of enteric vancomycin-resistant enterococci (VRE) in an intensive
care unit (ICU).
design. Thirty-month prospective observational study.
setting. ICU at a university-affiliated referral center.
patients. All patients with an ICU stay of 24 hours or more were eligible for the study.
intervention. Clinical active surveillance (CAS), involving culture of a rectal swab specimen for detection of VRE, was performed
on admission, weekly while the patient was in the ICU, and at discharge. Laboratory-based active surveillance (LAS), involving culture of
a stool specimen for detection of VRE, was performed on stool samples submitted for Clostridium difficile toxin detection.
results. Enteric colonization with VRE was detected in 309 (17%) of 1,872 patients. The CAS method initially detected 280 (91%) of
the 309 patients colonized with VRE, compared with 25 patients (8%) detected by LAS; colonization in 4 patients (1%) was initially detected
by analysis of other clinical specimens. Most patients with colonization (76%) would have gone undetected by LAS alone, whereas use of
the CAS method exclusively would have missed only 3 patients (1%) who were colonized. CAS cost $1,913 per month, or $57,395 for the
30-month study period. Cost savings of CAS from preventing cases of VRE colonization and bacteremia were estimated to range from
$56,258 to $303,334 per month.
conclusions. A patient-based CAS strategy for detection of enteric colonization with VRE was superior to LAS. In this high-risk setting,
CAS appeared to be the most efficient and cost-effective surveillance method. The modest costs of CAS were offset by the averted costs
associated with the prevention of VRE colonization and bacteremia.
Infect Control Hosp Epidemiol 2006; 27:1068-1075
From the Institute for Bio-Security, School of Public Health, Saint Louis University (B.N.S., L.M.M), the Saint Louis County Health Department (L.A.P.),
the Department of Health Management and Policy, School of Public Health, Saint Louis University (K.N.G.), and the Divisions of Infectious Diseases (S.J.L.)
and Pulmonary and Critical Care Medicine (M.K.), Washington University School of Medicine, St. Louis, Missouri.
Received August 18, 2005; accepted December 29, 2005; electronically published September 21, 2006.
䉷 2006 by The Society for Healthcare Epidemiology of America. All rights reserved. 0899-823X/2006/2710-0011$15.00.
Infections caused by multidrug-resistant organisms are as-
sociated with increased morbidity and mortality,
1-11
prolonged
hospital stays, and excess costs.
9,12-14
Adverse effects of infec-
tion with multidrug-resistant organisms lead not only to
higher healthcare costs but also to higher societal costs in
terms of decreased productivity and quality of life for patients
and their families.
15
Because enteric colonization with van-
comycin-resistant enterococci (VRE) is an important risk fac-
tor for VRE infection, prevention of colonization through
identification of others who are colonized, followed by im-
plementation of measures to control the spread of VRE after
their identification, seem imperative.
9,16-19
Existing guidelines recommend that healthcare facilities de-
velop and implement a plan to prevent and control the spread
of VRE.
9,20
However, definitive recommendations regarding
methods of surveillance have not been determined. Although
the costs of surveillance for enteric VRE have only begun to
be described,
5,21,22
the attributable costs to the healthcare sys-
tem associated with VRE bacteremia alone may justify sur-
veillance and control programs.
5,7,8,13,23,24
Identification of
VRE-colonized patients and implementation of contact iso-
lation have been shown to be cost-effective and may reduce
VRE-related morbidity and mortality in populations at high-
risk for VRE acquisition.
5,6,23,25-28
A variety of active and passive surveillance methods have
been used for detection of enteric VRE.
5,15,22,24,29-34
A few stud-
ies have compared active surveillance methods but were un-
able to conclude which method was superior.
31,32,34
The ob-
jectives of this study were to compare the performance of 2
active surveillance strategies for detection of enteric VRE and
to describe the associated costs and implications of these
strategies.
active surveillance for vre 1069
table 1. Demographic and Clinical Characteristics of 1,872 Intensive Care Unit
Patients by Vancomycin-Resistant Enterococci (VRE) Colonization Status
Variable
Colonization status of patients
VRE prevalent
a
(n p 182)
VRE incident
(n p 127)
VRE negative
(n p 1,563)
Categorical
White race 109 (60.0) 73 (57.5) 867 (55.5)
Male sex 74 (40.7) 59 (46.5) 761 (48.7)
Bacteremia, by causal pathogen
MRSA 14 (7.7) 14 (11.0) 126 (8.1)
Pseudomonas aeruginosa 3 (1.6) 4 (3.1) 26 (1.7)
Clostridium difficile 8 (4.4) 15 (11.8) 70 (4.5)
Mortality 79 (43.4) 47 (37.0) 396 (25.3)
Continuous
Age, y 62.3 Ⳳ 17.6 62.5 Ⳳ 15.9 58.9 Ⳳ 17.9
Duration of MICU stay, d
b
7.5 Ⳳ 8.7 16.9 Ⳳ 18.5 5.5 Ⳳ 7.6
Duration of hospitalization, d
b
23.2 Ⳳ 31.2 33.7 Ⳳ 27.8 14.7 Ⳳ 19.8
APACHE II score
c
24.4 Ⳳ 7.5 23.9 Ⳳ 6.3 21.1 Ⳳ 8.2
note. Data are no. (%) of patients or mean . See Methods for definitions ofvalue Ⳳ SD
colonization status. APACHE, Acute Physiology and Chronic Health Evaluation; MICU, medical
intensive care unit; MRSA, methicillin-resistant Staphylococcus aureus.
a
Four patients with VRE initially detected in culture of a nonsurveillance clinical isolate (ie,
culture of sterile body fluid, performed as a component of routine clinical care) were categorized
as having VRE identified through CAS.
b
Defined as the time of admission through the time of discharge.
c
From Knaus et al.
41
methods
Setting and Patients
Eligible participants were all patients admitted from July 1,
1997, through December 31, 1999, to the 19-bed medical
intensive care unit (ICU) at Barnes-Jewish Hospital (BJH), a
1,287-bed tertiary care facility in St. Louis, Missouri. Data
on patients residing in the ICU for 24 hours or more were
included; data from multiple admissions were combined if
subsequent admissions occurred 30 days or less after the ini-
tial admission. Data from only the first admission were in-
cluded in the analysis if subsequent admissions occurred more
than 30 days after the initial admission. Patients were ex-
cluded if microbiological data were incomplete or the pa-
tients’ medical records could not be reviewed. The research
review committees at Saint Louis University (St. Louis) and
Washington University Medical Center (St. Louis) approved
this study.
Study Design and Definitions
Clinical active surveillance (CAS) for VRE was defined as
prospective screening using rectal swab specimens. The CAS
method was performed by clinical staff who procured speci-
mens for detection of enteric VRE from all ICU patients at
ICU admission, ICU discharge, and every 7 days if the ICU
stay was 7 days or longer. Laboratory-based active surveillance
(LAS) was defined as screening of clinical stool specimens for
VRE that were originally collected for Clostridium difficile
screening in accordance with hospital-wide policy established
on October 1, 1996.
35
Patients with enteric VRE initially de-
tected in culture of a nonsurveillance clinical isolate (ie, culture
of sterile body fluid, performed as a component of routine
clinical care) were categorized as having VRE identified through
clinical specimens. Stool samples submitted by 12 patients for
C. difficile testing at the time of admission were classified as
CAS specimens. Patients with a stool specimen positive for C.
difficile toxin by cytotoxicity assay (Bartels) were categorized
as having C. difficile–associated diarrhea or colitis.
Patients with VRE detected by surveillance or clinical cul-
ture before or on admission to the ICU were classified as
having a prevalent case of VRE colonization. Patients with
enteric VRE acquired during ICU stay were characterized as
having an incident case of VRE colonization. Patients with
negative culture results from the time of admission through
the time of discharge were classified as being VRE negative.
The incidence density was calculated by dividing the number
of patients with an incident case of VRE colonization by the
number of inpatient-days in the ICU from either admission
until discharge (for patients without VRE colonization) or
from admission until the date of initial VRE detection (for
patients with VRE colonization).
Data Collection
During the study period, differential infection control strat-
egies were used for the scheduled rotation of antimicrobial
therapy and gown use, as described elsewhere.
6,29
Cost data