Prevention and Control of MRSA in ICUs
Prevention of MRSA transmission and control of ongoing dissemination among patients
receiving health care requires a number of preventive and control measures. The approach to
control is similar for adult and neonatal patients and for HA-MRSA and CA-MRSA.
Differences for adults versus neonates and for HA-MRSA versus CA-MRSA will be noted.
Screening Patients on Admission and During Hospitalization
The most important measures for control of MRSA in ICUs are active surveillance for patients
infected or colonized with MRSA at the time of admission followed by prompt isolation of
those patients identified as colonized or infected and weekly cultures for all other patients in
the ICU to detect acquisition of MRSA from patients who may have escaped detection on
admission, from colonized or infected HCWs, or from contaminated environmental surfaces
(41,51,74,81–98). It is important to identify every colonized patient so that all colonized as well
as infected patients can be placed on contact precautions. Surveillance cultures for MRSA
should always include samples from the anterior nares (81).
Patients are screened for colonization with MRSA by taking swab samples from the
anterior nares and other sites of possible MRSA colonization, such as the oropharynx, axilla,
inguinal area, perirectal areas, and from open wounds and skin eruptions. Samples are then
inoculated to broth or solid media containing antibiotics or other agents to select out MRSA.
Although effective, results are not immediately available due to the delay for incubation and
identification of isolates. More rapid techniques for detection of MRSA based on PCR have
been developed and published (99). Such techniques permit detection of MRSA from swab
specimens within two hours.
Screening for MRSA colonization and infection on admission is particularly important
for patients admitted from other hospitals, from long-term care facilities, or who have been
hospitalized in the past year. Although it is not yet clear as to the impact of CA-MRSA on the
influx of MRSA into hospitals, this potential reservoir for MRSA must be kept in mind. It may
be necessary to screen everyone entering the hospital from the community regardless of
whether they have one of the above-mentioned risk factors for MRSA colonization or infection.
Barrier Precautions
Gloves and a gown should be worn before entry of HCWs into rooms of patients isolated for
MRSA (100,101). There is good evidence that HCWs acquire MRSA on gloved and ungloved
hands and on gowns when in contact with patients colonized or infected with MRSA
(72,73,101). Hand hygiene should be practiced before and after glove use.
Whether or not masks are needed for contact precautions for MRSA is controversial. The
CDC has not recommended that masks be used for isolation of patients colonized or infected
by MRSA (75). Masks are recommended by the Society for Healthcare Epidemiology of
America (SHEA) Guidelines for preventing nosocomial transmission of multidrug-resistant
strains ofS. aureusandEnterococcus(81). However, the recommendation is categorized as a
type II. Definitive studies are needed to determine whether or not masks are needed for
isolation of patients with MRSA colonization or infection.
Decontamination of the Environment
ThereisevidencethattheenvironmentmaybeanimportantsourceforMRSAforpatient
colonization and infection (70,102,103). One study has shown that strains of MRSA survive for
about 7 to 10 months on glass surfaces (71). It was also shown that outbreak strains of MRSA
survived longer than sporadic strains. There is also evidence that enhanced disinfection is an
important measure for controlling epidemic MRSA (104,105). Thus, attention should be paid to
thorough cleaning and disinfection of environmental surfaces in patient rooms and other areas
where patients receive care.
Hand Hygiene
Hand hygiene is very important in conjunction with barrier precautions in preventing the
spread of MRSA between patients and from patients to HCWs (82). Hand hygiene practices
108 Mayhall