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The Importance of Controlling Methicillin-resistant Staphylococcus aureus
patients and healthcare workers carrying resistant bacteria, hand washing, The relationship between antibiotic use and rates of nosocomial MRSA has
and barrier precautions, have been suggested. Other studies have been described in a number of reviews.
Various studies have reported a
suggested that non-specific interventions such as hand washing and barrier positive association between antimicrobial use and incidence of MRSA
precautions that reduce transmission of all bacteria within a hospital will colonization or infection within the hospital setting, including the use of
disproportionately reduce the prevalence of colonization with resistant broad-spectrum cephalosporins and fluoroquinolones.
In some studies,
bacteria. These interventional strategies based on mathematical models other infection control procedures were instituted at the same time as
need to be subjected to scientific testing to confirm their efficacy and utility restriction of antibiotic use, thus complicating the interpretation of the data.
in clinical settings.
Few studies examining the relationship between risk factors and nosocomial
colonization and infection have identified antibiotic therapy as an
On a more pragmatic level, education of hospital staff about the epidemiology,
pathogenesis, and general routes of transmission of resistant bacteria within
the hospital environment, as well as the roles that antibiotic use plays in the
Education is required both to
emergence and spread of bacterial resistance, is important. Education is
disseminate basic information and
required both to disseminate basic information and to encourage compliance
with infection control measures that are subsequently implemented.
to encourage compliance with
infection control measures that are
A number of factors have been shown to influence risks for acquisition or
transmission of MRSA in the healthcare setting.
Factors known to be
associated with decreased acquisition and/or reduced hospital transmission
of MRSA include appropriate antibiotic use, proper hand hygiene, cohorting
care of infected or colonized patients, decreasing unnecessary patient independent risk factor.
Despite this, the bulk of the evidence seems to
contacts, and reducing length of stay for hospitalized patients. Other factors identify antibiotic therapy as a potential risk factor for MRSA colonization
thought to influence factors for nosocomial transmission of MRSA include and infection in the hospital setting, suggesting that better antibiotic
use of gowns and gloves by staff, isolation of infected or colonized patients, stewardship should result in decreased rates of nosocomial transmission of
improved staffing ratios, antibiotic cycling, decolonization of colonized staff MRSA. Another intervention to limit nosocomial transmission is known as
or patients, and disinfection of equipment or other objects in the antibiotic cycling. This involves cycling of formularies in the hospital. For
environment. Microbiological surveillance cultures of high-risk patients and instance, one class of antibiotics is used for the primary treatment of
staff have been postulated to be important in identifying patients harboring infections for a period of time and then, as resistance to that particular class
MRSA who serve as reservoirs for transmission and, therefore, may require occurs, a switch is made to a second class of antibiotics, for which resistance
heightened infection-control measures.
is rare or absent.
The Importance of Proper Hand Hygiene
The rationale for careful adherence to hand hygiene guidelines is that most
The risk of acquiring methicillin-resistant
nosocomial patient-to-patient transmission of MRSA occurs via the hands of
Staphylococcus aureus in the intensive healthcare workers. Proper hand hygiene clearly works in terms of reducing
nosocomial transmission of MRSA. Several task forces have reviewed the
care unit is increased by the severity of
available evidence and concluded that adherence to hand hygiene
illness, length of stay, intravascular device recommendations is associated with a reduced risk for healthcare cross-
Failure to observe proper hand hygiene is generally
use, and the intensity of exposure of
considered the leading cause of healthcare-associated infections and spread of
infected patients to antibiotics. multiresistant organisms such as MRSA. The guidelines recommend that visibly
dirty or contaminated hands should be washed with soap and water. Hands
not visibly soiled should be cleaned with an alcohol-based hand rub or,
Areas Where the Bacteria Can Be Controlled alternatively, antimicrobial soap and water before contact with patients or
One study grouped transmission risk factors into four categories that engaging in procedures. Hand washing should also occur after contact with
represent critical points at which MRSA may be potentially controlled within the intact or non-intact skin of patients, excretions, or mucous membranes.
the healthcare system. The critical points were: Hand decontamination is also necessary after contact with inanimate objects
or medical equipment in the vicinity of patients and after removing gloves.
•prevention of selection of methicillin-resistant isolates in a population of
S. aureus (antibiotic stewardship); Cohorting Care
•reduction in the pool of colonized patients or staff (discharge of Another effective infection control measure is cohorting. Cohorting care
colonized and infected patients/decolonization of carriers); means having staff provide care either for those patients already infected or
•prevention of patient-to-patient transmission (screening and alerts, hand colonized with MRSA or for those known not to be colonized or infected.
hygiene, cohorting, patient isolation, use of gowns and gloves); and Therefore, staff do not cross-cover infected/colonized and non-colonized
•prevention of infection in a colonized patient (i.e. nasal decolonization).
patients. Although not systematically studied, intuition suggests that
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