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Eradication of Methicillin-Resistant Staphylococcus aureus From a Health Center Ward and Associated Nursing Home
Pirkko Kotilainen, MD, PhD;
Marianne Routamaa, RN;
Reijo Peltonen, MD, PhD;
Pirjo Evesti, MD;
Erkki Eerola, MD, PhD;
Saara Salmenlinna, MSc;
Jaana Vuopio-Varkila, MD, PhD;
Tuire Rossi, MD
Arch Intern Med. 2001;161:859-863.
ABSTRACT
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Background Long-term health care facilities have been recognized as reservoirs
of multiresistant bacterial strains, especially methicillin-resistant Staphylococcus aureus (MRSA). Efforts to control MRSA in
this setting usually have been only partially effective. We describe herein
the eradication of epidemic MRSA from a Finnish health care center ward and
affiliated nursing home.
Methods The methods to control MRSA included (1) contact isolation precautions,
(2) screening for asymptomatic carriage, (3) eradication of carriage, and
(4) education of staff on hygienic measures. The first 6 patients with MRSA-positive
findings were referred without delay to the Infectious Diseases Unit of the
adjacent university hospital for eradication treatment. Later, an isolation
unit of 6 rooms was founded in the health care center, where the MRSA-colonized
patients were nursed as a separate cohort until they, in succession, were
referred to the Infectious Diseases Unit for decolonization.
Results From May 20 through August 17, 1993, the epidemic MRSA strain was isolated
from 8 long-term patients on the 40-bed ward of the health care center, 4
of the 59 residents of the nursing home, and 1 member of the staff. Eradication
of carriage was successful in all except 1 patient with dementia, who was
nursed in contact isolation in the health care center until his death 21 months
later.
Conclusions It is possible to eradicate MRSA from a long-term health care facility
even after 13 cases by applying strict control measures. Our experience may
be valuable in the future decision-making process for control of new and more
challenging multiresistant bacteria, eg, vancomycin-resistant strains of MRSA.
INTRODUCTION
DURING the past 2 decades, methicillin-resistant Staphylococcus aureus (MRSA) has become an increasingly common microorganism
in hospitals worldwide.1-4
However, in Finland, MRSA has remained uncommon, with only 0% to 0.5% of blood
isolates of S aureus annually resistant to methicillin.5-6 Although several hospital outbreaks
of MRSA occurred in Finland during the 1990s, the spread was effectively controlled
on most occasions.6 After containment of an
MRSA epidemic at the Turku University Central Hospital, Turku, in 1991-1992
with great effort and financial cost, rapid and vigorous infection control
approaches have been taken whenever MRSA has been encountered in any hospital
in southwestern Finland.
In a long-term health care setting, the risk for spread of MRSA is usually
small and carriage is more often associated with colonization than clinical
infection,7-8 thus posing a minor
threat to patients. Therefore, the control policy presently advised for MRSA
in extended health care facilities is flexible.7, 9-11
However, in an environment devoid of MRSA strains, an active policy may be
practicable and justified when infection or colonization first becomes manifest.
During the early summer of 1993, new cases of MRSA emerged weekly in the Mynamaki
Health Center (MHC) ward and associated nursing home in our medical district.
Because the exchange of patients is frequent between the MHC and the adjacent
university hospital as well as the 2 regional hospitals, we considered the
spread of MRSA in that institution to be a serious threat to the excellent
MRSA situation in the entire district. Therefore, we set a goal to contain
the outbreak or even to eradicate MRSA from the MHC.
PATIENTS AND METHODS
INSTITUTIONS
The MHC has 40 beds, mainly for elderly or geriatric patients with multiple
underlying diseases. The nursing home for the elderly has 59 beds and is situated
in the same building. Patients are often referred from the nursing home to
the MHC ward and vice versa.
The Turku University Central Hospital is a 1100-bed teaching facility
serving as a tertiary referral center for the southwestern part of the country
(Southwest Finland Medical District). At the time of the outbreak, the Department
of Infectious Diseases of that hospital had 16 beds.
MICROBIOLOGICAL TECHNIQUES
Screening and Follow-up Cultures
Initial screening for MRSA involved nasal, throat, and perineal swabbing
and cultures from all open wounds and skin lesions. If a patient was identified
as a carrier, the extent of MRSA colonization was determined by taking further
samples from the groin, axillae, urine, and feces. The cultures were taken
by means of rotating a premoistened cotton swab around the sampling site,
and the specimens were streaked directly on mannitol salt agar plates containing
1-ug/mL oxacillin.
A patient was usually deemed to be clear of MRSA when 3 sets of screening
swabs with negative findings were obtained after decolonization treatment.
However, colonization cultures were continued to verify persistent eradication
of MRSA. The schedule of the cultures taken was as follows: until the end
of 1993, cultures were taken from each patient twice or 4 times a month; during
1994, once or twice a month; and from 1995 onward, twice a year.
Identification of the Epidemic MRSA Strain
After incubating the plates at 35°C for 48 hours, they were evaluated
for the presence of growth and colonies were identified using standard procedures.
The isolates collected from the plates were identified as MRSA following the
guidelines recommended by the National Committee for Clinical Laboratory Standards.12 Based on disk diffusion and minimal inhibitory concentration
determined by the E test, the epidemic MRSA strain was resistant to methicillin
(minimal inhibitory concentration of oxacillin, >256 ug/mL) and possessed
the mecA gene. When typed using the International
Phage Set, the strain belonged to the phage type 54,84,85III/96V/95 (100 x
routine test dilution).
ERADICATION TREATMENT
Eradication courses involved topical treatment alone or combined with
systemic antimicrobial therapy. In addition, all patients used an antiseptic
detergent containing 4% chlorhexidine gluconate in daily washing or bathing.
Topical treatment consisted of the application of a cream containing 2% mupirocin
calcium 3 times a day locally at the colonized body sites for 5 to 7 days.13 The patients in whom colonization affected deeper
sites (especially the throat), where local treatment could not be administered,
also received systemic treatment. The antimicrobial agents used as systemic
therapy were selected based on in vitro susceptibility of the epidemic MRSA
strain. A patient was given simultaneously 2 different antimicrobial agents
to which the colonizing organism was susceptible, usually for 2 weeks. Two
patients had their dentures sterilized with heat simultaneous with the eradication
treatment, with the aim to prevent recolonization originating from contaminated
foreign material.14-15
RESULTS
OUTBREAK AND CONTROL MEASURES
From the end of May 20 through the August 17, 1993, the epidemic MRSA
strain was isolated from 8 long-term patients on the ward of 40 beds in the
MHC, 4 of the 59 residents of the nursing home, and 1 member of the staff.
From the index patient (patient 1), MRSA was isolated from a clinical specimen.
The clinical microbiology laboratory informed the University Hospital Infection
Control Team of the MRSA finding and a consultation was given. The patient
was immediately referred to the Department of Infectious Diseases, Turku University
Central Hospital, to be nursed in contact isolation, since no satisfactory
isolation facilities or previous experience with MRSA were available in the
MHC. Initial MRSA screening on the ward was limited to those patients who
had been in close contact with the index patient, ie, shared a room with her.
At the beginning of June, MRSA was isolated from 2 previous roommates
of the index patient. At this point, the University Hospital Infection Control
Team visited the MHC to delineate appropriate control measures for the containment
of MRSA. All patients of the ward were advised to undergo screening for MRSA.
Moreover, all MHC staff were given further education on hospital hygiene.
Special attention was focused on vigorous promotion of hand disinfection,
which was deemed necessary after every patient contact, and on appropriate
use of barriers in nursing.
A few days later, MRSA was isolated from a traumatic forehead wound
of a resident of the nursing home. This patient also had previously shared
a room on the MHC ward with the index patient. Soon thereafter, 2 male patients
sharing a room on the ward were shown to be MRSA carriers. A decision was
then made to screen the residents of the nursing home for MRSA.
In the middle of June, MRSA was isolated from 4 female MHC patients,
of whom 2 were roommates. The total number of patients with positive findings
for MRSA was now so large that the Department of Infectious Diseases could
not accommodate all new patients immediately. Thus, in the third week of June,
a separate unit of 6 rooms (6-10 beds total) was opened in the MHC, where
the MRSA-colonized patients were nursed by an assigned staff in contact isolation
until they could be admitted to the Department of Infectious Diseases for
decolonization. The isolation unit was established in a separate wing of the
hospital building, which had its own exit.
The staff assigned to work in the isolation unit was further trained
by the University Hospital Infection Control Team on nursing patients in contact
isolation, with special emphasis on the nature of MRSA as a pathogen and on
its modes of transmission. During an educational visit, each staff member
was given an opportunity to observe the daily routine in the Department of
Infectious Diseases, thus becoming better acquainted with infection control
measures. During the first months of the outbreak, the isolation unit staff
did not participate in the care of other patients of the ward.
After establishment of the isolation unit, further screening of contact
patients on the ward and in the nursing home revealed MRSA in 2, the first
in the end of June and the second (patient 12) in the middle of August 1993.
COLONIZED PATIENTS AND ERADICATION OF MRSA
Characteristics of the MRSA-positive patients and the quality and outcome
of eradication treatment are presented in Table 1. The sites of MRSA colonization are described in Table 2.
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Table 1. Characteristics of 12 Patients With Methicillin-Resistant Staphylococcus aureus*
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Table 2. Distribution of the Methicillin-Resistant Staphylococcus aureus Carriage at Various Body Sites Before First Eradication
Treatment*
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Two patients with mucosal or wound colonization received topical treatment
with mupirocin, whereas 9 patients who were throat carriers were administered
a combination of topical and systemic treatment. The most commonly used systemic
antimicrobial agent was clindamycin hydrochloride (given on 11 occasions),
followed by rifampin, fluoroquinolone (ciprofloxacin hydrochloride or ofloxacin),
and fusidic acid. More detailed data on drug regimens will be reported separately
(P.K., R.P., and T.R., unpublished data, December 2000).
Eradication was successful in 10 patients. Despite 3 courses of local
and systemic treatment, MRSA grew in cultures from patient 5 until his death
21 months later. The outcome cannot be assessed in the index patient in whom
findings for MRSA became negative during antituberculous treatment (active
also against MRSA), which was continued until her death 5 months later.
Of these 12 patients, 1 died in 1993, 2 in 1994, 3 in 1995, 3 in 1996,
and 2 in 1997. One patient is still alive.
CULTURES FROM THE STAFF AND CONTACT PATIENTS
Before establishing the isolation unit, the 89-member staff of the MHC
underwent screening for MRSA once by means of nasal swabs, with negative findings.
Subsequently, the 12-member staff working in the isolation unit underwent
screening once a month by means of nasal swabs. Transient carriage of MRSA
was detected in 1 nurse, with positive findings in 1 nasal culture.
After identification of the last positive case, all patients of the
ward and residents of the nursing home underwent screening for MRSA 2 to 4
times with negative findings. During the first 4 months after the beginning
of the outbreak, altogether 727 colonization cultures were taken in the MHC.
Afterward, colonization cultures were taken only from the patients with previous
findings positive for MRSA.
END OF THE OUTBREAK
For the decolonized patients, contact isolation measures were mainly
stopped by the end of 1993. However, the importance of adherence to a strict
hand-washing and/or disinfection routine after every patient contact was reinforced
repeatedly to the staff. The University Hospital Infection Control Team visited
the MHC 5 times during the outbreak. The decolonized patients continued to
occupy their rooms in the previous isolation wing, but over the years, new
patients were accommodated there. For the 1 patient with continued positive
findings for MRSA, contact isolation precautions were continued until his
death in March 1995. This was feasible because he was bedridden and, due to
dementia caused by multiple brain infarcts, unaware of the world around him.
COMMENT
Eradication of an epidemic MRSA strain from a Finnish long-term health
care facility succeeded by means of combined efforts of the local health center
personnel and the University Hospital Infection Control Team. We assume that
implementation of even the strictest control measures would have been in vain
without the devotion of the health care providers to bring this project to
a favorable end. The solidarity of the local health center personnel, including
the financial decision makers, was an indispensable strength of this endeavor,
bearing in mind that at the time of the outbreak there were no generally accepted
rules in Finland on how to control an MRSA outbreak in a long-term health
care facility. On the other hand, all available data were from countries with
a highly different epidemiological situation and, as such, not readily applicable
in an environment practically devoid of MRSA.
The initial decision to screen only a few close contacts of the index
patient concurred with the concept that the risk for the spread of MRSA in
a long-term health care setting is small and clinical infections are rare.9 This has been shown by Bradley et al,16
who studied MRSA colonization, transmission, and infection for 1 year in a
facility with endemic MRSA and found that 10% of newly admitted patients acquired
MRSA while in the facility but that the rate of infection was low. From that
and similar studies,17 the flexible MRSA control
policy currently advised for long-term health care facilities seems justified.
The mainstays of this strategy in many countries with a high prevalence of
MRSA include stringent hand-washing and hand-disinfection routines and surveillance
of clinical infection,7, 9-11
whereas MRSA screening, decolonization efforts, and isolation precautions
are discouraged.9 It is obvious that a more
stringent policy is unwarranted in facilities where a large number of long-term
patients harbor MRSA. It is equally obvious that in any extended health care
setting, enforcement of strict control measures (eg, patient isolation) for
long periods would be too disruptive and unrealistic.
However, in a facility with no previous MRSA, an active policy when
a new case is identified could be rewarding. This has been suggested also
by Simor et al,18 who managed to eradicate
a defined MRSA strain from a long-term health care facility in Canada after
identification of 5 cases. These authors underscored that chances of effective
control of MRSA are increased if infection control interventions are implemented
early, before the organism becomes endemic. Besides that report and the present
one, we are not aware of any other reports on eradication of an epidemic MRSA
strain that has spread to several patients in an extended health care facility.
In fact, the efforts to control MRSA in a long-term health care setting have
usually been only partially effective.19-21
The benefits of eradication of MRSA from an extended health care facility
are supported by the finding of Muder et al22
that colonization may be predictive of infection: in patients treated in a
long-term Veterans Affairs medical center, colonization by MRSA indicated
a significantly greater risk for infection than did colonization by methicillin-susceptible S aureus (25% vs 4%; P<.01).
According to Boyce et al,7 about 5% to 10%
of residents who acquire MRSA in long-term health care facilities will eventually
become infected. Thus, when it was obvious that MRSA was spreading in the
MHC, the intention of the local health authorities to prevent infection was
an indication to encourage a stringent eradication policy.
At present, the Nordic countries are among the very few in the world
in which MRSA strains are still uncommon.3, 6
These countries are characterized by implementation of national guidelines
for the control of multiresistant staphylococcal strains. In Finland, national
guidelines for MRSA were issued in 1995.6 The
cornerstones of our control policy involve screening of all patients who have
been previously treated in hospitals abroad or with a known MRSA problem at
the time of admission to a Finnish hospital, and nursing these patients, and
all patients known to have positive findings for MRSA, in private rooms using
contact isolation precautions until colonization cultures have proved to be
negative. In the Turku University Central Hospital area, a similarly strict
policy was adopted after containment of the 1991-1992 MRSA epidemic. Consequently,
had MRSA spread and become endemic in the MHC, screening and contact isolation
precautions would have been instituted on all future patients referred from
this facility to other hospitals in southwest Finland. This option was evidently
seen by the MHC leaders as another strong point to favor aggressive eradication
efforts.
The University Hospital Infection Control Team also had other concerns.
In many countries, nursing and residential homes with endemic MRSA have been
responsible for spreading this microorganism into neighboring hospitals.17, 23-24 On this basis, the
potential development of an MRSA reservoir in one of our health care centers
was estimated to jeopardize severely the previously stable epidemiological
situation in the entire area. The control of multiresistant microorganisms
in our medical district was already supervised by the University Hospital
Infection Control Team. This guaranteed, at least to some extent, compliance
with a stringent MRSA policy also in the surroundings of Mynamaki. Because
of our mutual interest to keep the MRSA incidence low in this region, we believe
that our goal to eradicate MRSA from the MHC was reasonable. Then again, such
a decision would have been unwise had there not been a conviction that a comparable
policy was followed in the neighboring hospitals. The prudent nature of this
operation in the Southwest Finland Medical District is supported by the continuously
excellent MRSA situation 7 years later: we did not detect any intrahospital
transmission of MRSA during the past year.
At present, a stringent policy aimed at searching for MRSA-colonized
patients and eradication of carriage may be reasonable and feasible in a few
countries only. However, the value of the present report lies in the description
of successful control of any epidemic multiresistant strain, not specifically
MRSA. It is important to remember that although the battle against MRSA appears
to be lost in many countries, there may be new and more challenging strains
of S aureus to come. To successfully gain control
of future multiresistant strains, one should learn from earlier failures and
accomplishments.
CONCLUSIONS
Eradication of MRSA from a health care center ward and associated nursing
home succeeded by following a stringent control policy. We believe that for
MRSA, such a policy may be reasonable in an environment with no endemic strains.
An educated and motivated staff smoothly cooperating with the University Hospital
Infection Control Team, ardent support from the health care center leadership,
and a uniform policy for the control of multiresistant strains in the medical
district were the strengths of the endeavor. Our experience may be valuable
in the future decision-making process for control of emerging multiresistant
bacteria, eg, vancomycin-resistant strains of MRSA.
AUTHOR INFORMATION
Accepted for publication October 23, 2000.
This work was supported by a grant from the EVO Foundation of the Turku
University Central Hospital, Turku, Finland.
We thank Kirsti Tuomela, Ritva Scotford, and Elina Siren for expert
technical assistance.
Corresponding author and reprints: Pirkko Kotilainen, MD, Department
of Medicine, Turku University Central Hospital, Kiinamyllynkatu 4-8, 20520
Turku, Finland (e-mail: pirkko.kotilainen{at}utu.fi).
From the Departments of Medicine (Drs Kotilainen, Peltonen, and Rossi)
and Surgery (Ms Routamaa and Dr Evesti), Turku University Central Hospital,
the Department of Medical Microbiology, Turku University (Dr Eerola), and
the Antimicrobial Research Laboratory, National Public Health Institute (Dr
Kotilainen), Turku, Finland; the Mynamaki Health Center, Mynamaki, Finland
(Dr Evesti); and the Department of Bacteriology, National Public Health Institute,
Helsinki, Finland (Ms Salmenlinna and Dr Vuopio-Varkila).
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