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Methicillin-resistant S.
aureus is a variant of S. aureus which is considered to be
resistant to all beta-lactam antibiotics (including penicillins,
cephalosporins, and cephamicins). It may also be resistant to one or more
other classes of antibiotics.
MRSA strains have been
identified as a major source of healthcare-acquired infections and outbreaks
in the U.S. and Florida. For over four decades, MRSA has presented a
challenge for hospitals attempting to control this organism. In recent
years, long-term acute care hospitals, long-term care facilities,
rehabilitation centers, and small community hospitals have seen increasing
numbers of cases. Part of their challenge is the need to be continuously on
guard against the frequent admissions and transfers of patients with MRSA
infections within these settings.
More recently, MRSA has
also been increasing in the community in individuals without
healthcare-associated risk factors. Organisms that cause
Community-Associated MRSA (CA-MRSA) infections are genetically distinct from
the typical Healthcare-Associated MRSA (HA-MRSA) commonly encountered in
healthcare settings.
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Healthcare-Associated MRSA (HA-MRSA) Infection
and colonization with HA-MRSA are typically seen in older individuals
with one or more of the following risks: long hospital stay; multiple
hospitalizations; more than 65 years old; multiple invasive procedures;
wounds; severe underlying disease; receiving broad-spectrum antibiotics;
undergoing hemodialysis; and intravenous drug use. Resistance to
multiple classes of antimicrobial agents is common.
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Community-Associated MRSA (CA-MRSA)
Community-Associated MRSA is frequently seen in younger persons and
involve skin and soft tissue infections. Risk factors for infection are
referred to as the 5 Cs: Crowding, frequent skin-to-skin Contact, Cuts
or abrasions, Contaminated items and surfaces, and lack of Cleanliness.
Frequently, community-associated cases have initially been misdiagnosed
as spider bites. This misdiagnosis prevents timely treatment and may
increase the chance of transmission to others. Outbreaks of these
infections have been described in numerous groups including people found
in correctional facilities (jails and prisons), sport teams, men who
have sex with men, commercial fishermen, and minority populations.
Resistance to multiple classes of antimicrobials is uncommon. Many of
the CA-MRSA infections may be effectively treated with good wound care
with or without oral antibiotics, while more resistant strains may
require intravenous vancomycin.
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