Download Understanding MRSA (Methicillin resistant Staphylococcus aureus

Understanding MRSA (Methicillin resistant Staphylococcus aureus)
What is MRSA?
Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium that causes
infections in different parts of the body. It's tougher to treat than most strains of
staphylococcus aureus -- or staph -- because it's resistant to some commonly
used antibiotics.
The symptoms of MRSA depend on where you're infected. Most often, it causes
mild infections on the skin, causing pimples or boils. But it can also cause more
serious skin infections or infect surgical wounds, the bloodstream, the lungs, or
the urinary tract.
Though most MRSA infections aren't serious, some can be life-threatening. Many
public health experts are alarmed by the spread of tough strains of MRSA.
Because it's hard to treat, MRSA is sometimes called a "super bug."
A Closer Look at MRSA
What causes MRSA?
Garden-variety staph are common bacteria that can live on our bodies. Plenty of
healthy people carry staph without being infected by it. In fact, 25-30% of us have
staph bacteria in our noses.
But staph can be a problem if it manages to get into the body, often through a cut.
Once there, it can cause an infection. Staph is one of the most common causes of
skin infections in the U.S. Usually, these are minor and don't need special
treatment. Less often, staph can cause serious problems like infected wounds or
pneumonia.
Staph can usually be treated with antibiotics. But over the decades, some strains
of staph -- like MRSA -- have become resistant to antibiotics that once destroyed
it. MRSA was first discovered in 1961. It's now resistant to methicillin, amoxicillin,
penicillin, oxacillin, and many other antibiotics.
While some antibiotics still work, MRSA is constantly adapting. Researchers
developing new antibiotics are having a tough time keeping up.
Who gets MRSA?
MRSA is spread by contact. So you could get MRSA by touching another person
who has it on the skin. Or you could get it by touching objects that have the
bacteria on them. MRSA is carried, or "colonized," by about 1% of the population,
although most of them aren't infected.
MRSA infections are most common among people who have weak immune
systems and are living in hospitals, nursing homes, and other heath care centers.
Infections can appear around surgical wounds or invasive devices, like catheters
or implanted feeding tubes. Rates of infection in hospitals, especially intensive
care units, are rising throughout the world. In U.S. hospitals, MRSA causes more
than 60% of staph infections.
Community-Associated MRSA (CA-MRSA)
But MRSA is also showing up in healthy people who have not been living in the
hospital. This type of MRSA is called community-associated MRSA, or CA-MRSA.
The CDC reports that in 2007, 14% of people with MRSA infections had CAMRSA.
Studies have shown that rates of CA-MRSA infection are growing fast. One study
of children in south Texas found that cases of CA-MRSA had a 14-fold increase
between 1999 and 2001.
CA-MRSA skin infections have been identified among certain populations that
share close quarters or experience more skin-to-skin contact. Examples are team
athletes, military recruits, and prisoners. However, more and more CA-MRSA
infections are being seen in the general community as well, especially in certain
geographic regions.
It's also infecting much younger people. In a study of Minnesotans published in
The Journal of the American Medical Association, the average age of people with
MRSA in a hospital or healthcare facility was 68. But the average age of a person
with CA-MRSA was only 23.
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WebMD Medical Reference
View Article Sources
Reviewed by Debbie Bridges, MD on December 05, 2009
© 2009 WebMD, LLC. All rights reserved.
©2005-2007 WebMD, Inc. All rights reserved.
WebMD does not provide medical advice, diagnosis or treatment.
Original Article:http://www.mayoclinic.com/health/mrsa/DS00735

Definition

Symptoms

Causes

Risk factors

When to seek medical advice

Tests and diagnosis

Treatments and drugs

Prevention
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Definition
MRSA infection is caused by Staphylococcus aureus bacteria — often called
"staph." MRSA stands for methicillin-resistant Staphylococcus aureus. It's a strain
of staph that's resistant to the broad-spectrum antibiotics commonly used to treat
it. MRSA can be fatal.
Most MRSA infections occur in hospitals or other health care settings, such as
nursing homes and dialysis centers. It's known as health care-associated MRSA,
or HA-MRSA. Older adults and people with weakened immune systems are at
most risk of HA-MRSA. More recently, another type of MRSA has occurred among
otherwise healthy people in the wider community. This form, communityassociated MRSA, or CA-MRSA, is responsible for serious skin and soft tissue
infections and for a serious form of pneumonia.
Symptoms
Photos of staph infections
Staph skin infections, including MRSA, generally start as small red bumps that
resemble pimples, boils or spider bites. These can quickly turn into deep, painful
abscesses that require surgical draining. Sometimes the bacteria remain confined
to the skin. But they can also penetrate into the body, causing potentially lifethreatening infections in bones, joints, surgical wounds, the bloodstream, heart
valves and lungs.
Causes
MRSA is a strain of staph that's resistant to the broad-spectrum antibiotics
commonly used to treat it.
Staph infections
Staph bacteria are normally found on the skin or in the nose of about one-third of
the population. If you have staph on your skin or in your nose but aren't sick, you
are said to be "colonized" but not infected. Healthy people can be colonized and
have no ill effects. However, they can pass the germ to others.
Staph bacteria are generally harmless unless they enter the body through a cut or
other wound, and even then they often cause only minor skin problems in healthy
people. However, staph infections can cause serious illness. This most often
happens in older adults and people who have weakened immune systems, usually
in hospitals and long term care facilities. But in the past several years, serious
infections have been occurring in otherwise healthy people in the community, for
example athletes who share equipment or personal items.
Antibiotic resistance
Although the survival tactics of bacteria contribute to antibiotic resistance, humans
bear most of the responsibility for the problem. Leading causes of antibiotic
resistance include:

Unnecessary antibiotic use. Like other superbugs, MRSA is the result of
decades of excessive and unnecessary antibiotic use. For years, antibiotics
have been prescribed for colds, flu and other viral infections that don't
respond to these drugs, as well as for simple bacterial infections that
normally clear on their own.

Antibiotics in food and water. Prescription drugs aren't the only source of
antibiotics. In the United States, antibiotics can be found in livestock. These
antibiotics find their way into municipal water systems when the runoff from
feedlots contaminates streams and groundwater.

Germ mutation. Even when antibiotics are used appropriately, they
contribute to the rise of drug-resistant bacteria because they don't destroy
every germ they target. Bacteria live on an evolutionary fast track, so germs
that survive treatment with one antibiotic soon learn to resist others. And
because bacteria mutate much more quickly than new drugs can be
produced, some germs end up resistant to just about everything. That's why
only a handful of drugs are now effective against most forms of staph.
Risk factors
Because hospital and community strains of MRSA generally occur in different
settings, the risk factors for the two strains differ.
Risk factors for community-associated MRSA (CA-MRSA)

Young age. CA-MRSA can be particularly dangerous in children. Often
entering the body through a cut or scrape, MRSA can quickly cause a
widespread infection. Children may be susceptible because their immune
systems aren't fully developed or they don't yet have antibodies to common
germs. Children and young adults are also much more likely to develop
dangerous forms of pneumonia, which can result from CA-MRSA, than older
people are.

Participating in contact sports. CA-MRSA has affected sports teams. The
bacteria spread easily through cuts and abrasions and skin-to-skin contact.

Sharing towels or athletic equipment. CA-MRSA has spread among
athletes sharing razors, towels, uniforms or equipment.

Having a weakened immune system. People with weakened immune
systems, such as those living with HIV/AIDS, are more likely to have severe
CA-MRSA infections.

Living in crowded or unsanitary conditions. Outbreaks of CA-MRSA
have occurred in military training camps and in American and European
prisons.

Association with health care workers. People who are in close contact
with health care workers are at increased risk of serious staph infections.
In addition to these risk factors, CA-MRSA is also spreading through certain
groups of gay men. A study published in the Annals of Internal Medicine found a
new strain of MRSA spreading rapidly among gay men in Boston and San
Francisco. For example, gay men in San Francisco were 13 times more likely to
be infected than others in the city.
Risk factors for health care-associated MRSA (HA-MRSA)

A current or recent hospitalization. MRSA remains a concern in hospitals,
where it can attack those most vulnerable — older adults and people with
weakened immune systems, burns, surgical wounds or serious underlying
health problems. This is particularly true if you have a hospital stay of more
than 14 days. A 2007 report from the Association for Professionals in
Infection Control and Epidemiology estimated that 46 out of every 1,000
people hospitalized are infected or colonized with MRSA.

Living in a long term care facility. MRSA is also prevalent in these
facilities. Carriers of MRSA have the ability to spread it, even if they're not
sick themselves.

Invasive devices. People who are on dialysis, are catheterized, or have
feeding tubes or other invasive devices are at higher risk.

Recent antibiotic use. Treatment with fluoroquinolones (ciprofloxacin,
ofloxacin or levofloxacin) or cephalosporin antibiotics can increase the risk of
HA-MRSA.
When to seek medical advice
Keep an eye on minor skin problems — pimples, insect bites, cuts and scrapes —
especially in children. If wounds become infected, see your doctor.
Signs and symptoms of a wound infection

Redness, warmth and tenderness of the wound

Pus — a yellowish-white fluid that may have a foul smell

Fever
Ask to have any skin infection tested for MRSA before starting antibiotic therapy.
Some drugs that treat ordinary staph aren't effective against MRSA, and their use
could lead to serious illness and more resistant bacteria.
Tests and diagnosis
Doctors diagnose MRSA by checking a tissue sample or nasal secretions for signs
of drug-resistant bacteria. The sample is sent to a lab where it's placed in a dish of
nutrients that encourage bacterial growth (culture). But because it takes about 48
hours for the bacteria to grow, newer tests that can detect staph DNA in a matter
of hours are now becoming more widely available.
In the hospital, you may be tested for MRSA if you show signs of infection or if you
are transferred into a hospital from another health care setting where MRSA is
known to be present. You may also be tested if you have had a previous history of
MRSA.
Treatments and drugs
Both hospital- and community-associated strains of MRSA still respond to certain
medications. In hospitals and care facilities, doctors often rely on the antibiotic
vancomycin to treat resistant germs. CA-MRSA may be treated with vancomycin
or other antibiotics that have proved effective against particular strains. Although
vancomycin saves lives, it may become less effective as well. Some hospitals are
already seeing strains of MRSA that are less easily killed by vancomycin.
In some cases, antibiotics may not be necessary. For example, doctors may drain
a superficial abscess caused by MRSA rather than treat the infection with drugs.
Prevention
Hospitals are fighting back against MRSA infection by using surveillance systems
that track bacterial outbreaks and by investigating products such as antibioticcoated catheters and gloves that release disinfectants.
Still, the best way to prevent the spread of germs is for health care workers to
wash their hands frequently, to properly disinfect hospital surfaces and to take
other precautions, such as wearing gowns and gloves when working with people
infected with resistant bacteria.
In the hospital, people who are infected or colonized with MRSA are placed in
isolation to prevent the spread of MRSA. Visitors and health care workers caring
for people in isolation may be required to wear protective garments and must
follow strict hand-washing procedures.
What you can do in the hospital
Here's what you can do to protect yourself, family members or friends from health
care-associated infections.

Ask all hospital staff to wash their hands or use an alcohol-based hand
sanitizer before touching you — every time.

Wash your own hands frequently.

Make sure that intravenous tubes and catheters are inserted under sterile
conditions, for example, the person inserting them wears a gown, gloves
and mask and sterilizes your skin first.
What you can do in your community
Protecting yourself from MRSA in your community — which might be just about
anywhere — may seem daunting, but these common-sense precautions can help
reduce your risk:

Wash your hands. Careful hand washing remains your best defense
against germs. Scrub hands briskly for at least 15 seconds, then dry them
with a disposable towel and use another towel to turn off the faucet. Carry a
small bottle of hand sanitizer containing at least 60 percent alcohol for times
when you don't have access to soap and water.

Keep personal items personal. Avoid sharing personal items such as
towels, sheets, razors, clothing and athletic equipment. MRSA spreads on
contaminated objects as well as through direct contact.

Keep wounds covered. Keep cuts and abrasions clean and covered with
sterile, dry bandages until they heal. The pus from infected sores may
contain MRSA, and keeping wounds covered will help keep the bacteria
from spreading.

Shower after athletic games or practices. Shower immediately after each
game or practice. Use soap and water. Don't share towels.

Sit out athletic games or practices if you have a concerning infection. If
you have a wound that's draining or appears infected — for example, is red,
swollen, warm to the touch or tender — consider sitting out athletic games or
practices until the wound has healed.

Sanitize linens. If you have a cut or sore, wash towels and bed linens in a
washing machine set to the "hot" water setting (with added bleach, if
possible) and dry them in a hot dryer. Wash gym and athletic clothes after
each wearing.

Get tested. If you have a skin infection that requires treatment, ask your
doctor if you should be tested for MRSA. Doctors may prescribe drugs that
aren't effective against antibiotic-resistant staph, which delays treatment and
creates more resistant germs. Testing specifically for MRSA may get you the
specific antibiotic you need to effectively treat your infection.

Use antibiotics appropriately. When you're prescribed an antibiotic, take
all of the doses, even if the infection is getting better. Don't stop until your
doctor tells you to stop. Don't share antibiotics with others or save unfinished
antibiotics for another time. Inappropriate use of antibiotics, including not
taking all of your prescription and overuse, contributes to resistance. If your
infection isn't improving after a few days of taking an antibiotic, contact your
doctor.