Baylor University Medical Center Proceedings April 2014, Volume 27, Number 2 | Page 9
Impact of a surveillance screening program on rates of
methicillin-resistant Staphylococcus aureus infections with a
comparison of surgical versus nonsurgical patients
Andrew Jennings, MD, Monica Bennett, PhD, Tammy Fisher, RN, BBA, and Alan Cook, MD
Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of
health care–associated infection. The overall effectiveness of surveillance
screening programs is not well established. A retrospective cohort study
was performed to evaluate the impact of a surveillance screening program
on the rates of health care–associated MRSA infection (HA-MRSA-I) at a
single institution. A subset of surgical patients was analyzed separately.
Multivariate regression techniques were used to identify predictors of the
desired outcomes. The overall MRSA infection rate was 1.3% in the before
cohort and 3.2% in the after cohort. After excluding patients with a history of MRSA infection or MRSA colonization, HA-MRSA-I decreased from
1.2% to 0.87%. There was a similar overall increase in the surgical group,
1.4% to 2.3%, and decrease in HA-MRSA-I, 1.4% to 1.0% (P < 0.001).
For all patients, surgery, African American race, and increased length of
stay conferred an increased likelihood of HA-MRSA-I. Females and patients
in the after cohort had a lower risk of HA-MRSA-I (P < 0.01). In the after
cohort, the results were similar, with surgery, African American race, and
length of stay associated with an increased risk, and female sex associated
with a decreased risk (P < 0.05). African American race and increased
age had a higher likelihood of screening positive for MRSA colonization,
while the surgical group, females, and Hispanic patients were less likely
(P < 0.05). HA-MRSA-I was associated with a higher mortality among all
patients (P < 0.001). Mortality rates were similar with HA-MRSA-I for all
patients (10.8% vs 9.5%, P = 0.55) and in the surgical group (8.3% vs
6.8%, P = 0.58). In conclusion, surveillance programs may be effective
in decreasing HA-MRSA-I. Further studies are needed to determine how
to reduce transmission, particularly among African Americans and those
with increased lengths of stay.
ethicillin-resistant Staphylococcus aureus (MRSA) is a
significant cause of health care–associated infection (1)
and is associated with increased hospital mortality (2,
3). In addition, MRSA is the leading cause of surgical
site infection (4, 5). In 2003, the Society of Healthcare Epidemiology of America released guidelines strongly supporting the
use of active surveillance cultures and contact isolation programs
(6). A decrease in overall health care–associated MRSA infections
(HA-MRSA-I) has since been demonstrated across a wide range
of clinical and geographical settings in the United States (7).
Surveillance programs have also proven to be effective in MRSA
outbreaks in the intensive care unit (ICU) setting (8). Despite a
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Proc (Bayl Univ Med Cent) 2014;27(2):83–87
decrease in overall HA-MRSA-I rates after implementation of
active surveillance culture programs, the effect of HA-MRSA-I
rates on specific patient populations, including patients undergoing
invasive surgical procedures, is not well established (9, 10).
The purpose of this study was to evaluate rates of HA-MRSAI before and after implementation of a hospitalwide screening
program at a large teaching hospital with a high surgical volume.
We examined the effect of this infection control initiative in the
overall hospital population as well as for patients undergoing a
wide range of common surgical procedures among a variety of
specialties. We hypothesized that rates of HA-MRSA-I would
decrease after implementation of a screening program, both
hospitalwide and for patients undergoing surgical procedures.
METHODS
This institutional review board–approved retrospective cohort
study took place at Baylor University Medical Center at Dallas, a
1000-bed academic medical center and level I trauma center in a
large metropolitan area. Our current practice involves performing
nasal swab MRSA polymerase chain reaction (PCR) screens on all
patients who meet one of the following screening criteria: a prior
history of MRSA colonization or infection (patient is placed in contact isolation); hospitalization within the preceding year; transfer
from an extended care facility; presence of open or draining skin
wounds (patient is placed in contact isolation); current admission
to ICU; or current hemodialysis. Standard barrier and isolation
precautions, including gown and gloves, are applied to all patients
with a positive screen. With the exception of several four-bed pods
in the surgical intensive care unit, all rooms are single rooms.
A hospitalwide MRSA surveillance program was implemented in January 2009. Prior to this initiative, standard barrier
and isolation practices were implemented only if patients had a
documented MRSA infection or if the patient or patient’s history
indicated prior MRSA infection. For purposes of this study, the
term “MRSA infection” is used if a positive MRSA culture was
From the Department of Surgery, Baylor University Medical Center at Dallas.
Dr. Jennings is now with the Department of Surgery at The University of Texas
Southwestern Medical Center, Dallas, Texas.
Corresponding author: Andrew Jennings, MD, Department of Surgery, The
University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard,
Dallas, TX 75390-9158 (e-mail: [email protected]).
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