Ms. Terpenning et al., COLONIZATION AND INFECTION WITH ANTIBIOTIC-RESISTANT BACTERIA IN A LONG-TERM-CARE FACILITY, Journal of the American Geriatrics Society, 42(10), 1994, pp. 1062-1069
OBJECTIVE: To assess colonization and infection with methicillin-resis
tant Staphylococcus aureus (MRSA), high-level gentamicin-resistant ent
erococci (R-ENT) and gentamicin and/or ceftriaxone-resistant Gram-nega
tive bacilli (R-GNB) and the factors that are associated with coloniza
tion and infection with these organisms. DESIGN: Monthly surveillance
for colonization and infection over a period of 2 years. In the second
year, an intervention to decrease MRSA colonization by the use of mup
irocin ointment was carried out. SETTING: Long-term care facility atta
ched to an acute care Veterans Affairs Medical Center. PATIENTS: A tot
al of 551 patients in the facility were followed for a period of 2 yea
rs. MEASUREMENTS: Colonization and infection rates with MRSA, R-ENT, a
nd R-GNB. Analysis of risk factors associated with colonization and in
fection with these three groups of organisms. MAIN RESULTS: In the fir
st year, colonization rates were highest for MRSA (22.7+/-1% patients
colonized each month) and R-ENT (20.2+/-l%) and lower for R-GNB (12.6/-1%). After introduction of decolonization of nares and wounds with m
upirocin, the rate of MRSA colonization fell significantly to 11.5 +/-
1.8%, but rates remained unchanged for R-ENT and R-GNB. Risk factors
for MRSA colonization included the presence of wounds and decubitus ul
cers. For R-ENT, the presence of wounds, renal failure, intermittent u
rethral catheterization, low serum albumin, and poor functional level
were significant. For R-GNB, intermittent urethral catheterization, ch
ronic renal disease, inflammatory bowel disease, presence of wounds, a
nd prior pneumonia were significantly associated with colonization. Ov
erall, of infections caused by known organisms, 49.6% were due to MRSA
, R-ENT, or R-GNB, and 50.4% were due to susceptible organisms. Infect
ions were more commonly due to R-GNB (21.1% of all infections) than to
R-ENT (8.3%) or MRSA (4.6%). The most common infections were urinary
tract infections (42.9% of all infections) and skin and soft tissue in
fections (31.9% of all infections). Risk factors for MRSA infections w
ere diabetes mellitus and peripheral vascular disease for R-GNB infect
ions were intermittent urethral catheterization and indwelling urethra
l catheters, and no one factor was associated with R-ENT infection. CO
NCLUSIONS: In our long-term care facility, colonization with resistant
MRSA and R-ENT was more common than R-GNB, but infections were more o
ften due to R-GNB than R-ENT and MRSA. Several host factors, which pot
entially could be modified in order to prevent infections, emerged as
important in colonization and infection with these antibiotic-resistan
t organisms.