MRSA
Introduction
MRSA stands for meticillin-resistant Staphylococcus aureus. MRSA is a common skin bacterium that is resistant to a range of antibiotics including meticillin, which is a type of penicillin antibiotic.
'Meticillin-resistant' means the bacteria are unaffected by meticillin, a type of antibiotic that used to be able to kill them.
An MRSA infection means the bacteria have got into the body through a break in the skin (see below) and multiplied, causing symptoms.
The symptoms of MRSA infection vary depending on which part of the body is infected, but there is often redness and swelling at the site of infection.
Colonisation
About one in three of us carries the Staphylococcus aureus (SA) bacteria in our nose or on the surface of our skin (especially in folds like the armpit or groin) without developing an infection. This is known as being colonised by the bacteria.
In hospitals, the proportion of people colonised by MRSA is higher because of more contact with infected cases (see below).
People can carry MRSA for a few hours or days or sometimes for weeks or months. They are unaware they are carriers because the bacteria do not harm them or cause symptoms, unlike people who are infected with MRSA.
How infection happens
If SA bacteria get into the body through a break in the skin, they can cause infections such as boils, an abscess or impetigo. If they get into the bloodstream they can cause more serious infections, such as blood poisoning (see MRSA infection - symptoms).
Who is most at risk?
MRSA will not normally infect a healthy person. Although it is possible for people outside hospital to become infected, MRSA infections are most common in people who are already in hospital. This is because:
- they often have an entry point for the bacteria to get into their body, such as a surgical wound or a catheter
- they tend to be older, sicker and weaker than the general population, which makes them more vulnerable to infection
- they are surrounded by a large number of other patients and staff, so the bacteria can spread easily (through direct contact with other patients or staff, or via contaminated surfaces)
For more information, see the list of at-risk groups.
Screening for MRSA
All NHS patients going into hospital for a relevant planned procedure are screened for MRSA beforehand. This helps the NHS reduce the chance of patients getting an MRSA infection or passing MRSA on to another patient. For more information, see Screening.
Treatment
Bacterial infections are treated with antibiotics. However, MRSA bacteria are resistant to meticillin and usually to some of the other antibiotics that are normally used to treat SA infections. Therefore, MRSA infections are more difficult to treat than other bacterial infections.
Antibiotics can still be used to treat MRSA, but you may need a much higher dose over a much longer period, or treatment with an antibiotic to which the bacteria are not resistant (see MRSA infection - treatment).
Healthcare staff, patients and hospital visitors can take simple hygiene measures, such as regular hand washing, to help prevent the spread of MRSA and stop infection (see MRSA infection - prevention).
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Symptoms
The symptoms of an MRSA infection will depend on what part of the body is infected. MRSA can infect a range of body tissues and organs.
Skin infection
Most Staphylococcus aureus (SA) infections are skin infections, including:
- boils (pus-filled infections of hair follicles),
- abscesses (collections of pus in pockets under the skin),
- styes (infection of glands in the eyelid),
- carbuncles (large pus-filled lumps under the skin)
- cellulitis (infection of the skin and the fat and tissues that lie immediately beneath it), and
- impetigo (a highly contagious skin infection that produces pus-filled blisters).
You should keep an eye on minor skin problems like spots, cuts or burns. If you have a wound that becomes infected you should see your doctor.
An MRSA-infected wound will become red, swollen and tender, with yellow pus seeping from it. Skin ulcers, such as pressure ulcers, are often sites of infection.
Bloodstream infection
If MRSA bacteria enter into the bloodstream from your skin, they can affect almost any part of the body. They can cause:
- septicaemia (blood poisoning),
- septic shock (widespread infection of the blood that leads to a fall in blood pressure and organ failure),
- severe joint problems (septic arthritis),
- bone marrow infection (osteomyelitis),
- internal abscesses anywhere within the body,
- meningitis,
- pneumonia, or
- infection of the heart lining (endocarditis).
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Causes
MRSA will not normally infect a healthy person. Although it is possible for people outside hospital to become infected, MRSA infections are most common in people who are already in hospital because:
- They often have an entry point for the bacteria to get into their body, such as a surgical wound, a catheter or an intravenous tube. For example, if a patient colonised with MRSA bacteria touches their wound or catheter tube, they may infect themselves.
- They tend to be older, sicker and weaker than the general population, which makes them more vulnerable to infection.
- They are surrounded by a large number of other patients and staff, so the bacteria can spread easily.
How it spreads
MRSA bacteria are usually spread through skin-to-skin contact with someone who has an MRSA infection or who is colonised by the bacteria.
The bacteria can also spread through contact with towels, sheets, clothes, dressings or other objects that have been used by someone colonised or infected with MRSA.
During bed making, for example, skin scales from an infected or colonised person may become airborne and contaminate nearby surfaces.
MRSA can survive for long periods on objects or surfaces such as door handles, sinks, floors and cleaning equipment.
At-risk groups
Those most at risk of MRSA infection are those who:
- have a weakened immune system, such as the elderly, newborn babies and those with a long-term health condition such as diabetes
- have an open wound
- have a catheter (a plastic tube inserted into the body to drain fluid) or an intravenous drip
- have a burn or cut on their skin
- have a severe skin condition such as leg ulcer or psoriasis
- have recently had surgery
- have to take frequent courses of antibiotics
Although MRSA infections usually develop in those being treated in hospital, particularly patients in intensive care units and on surgical wards, it is possible for hospital staff or visitors to become infected if they are in one of these higher-risk groups.
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Diagnosis
An MRSA infection is most commonly diagnosed using a blood, urine, tissue or sputum (spit) culture.
This involves taking a sample of one or more of these substances and placing them in a dish of nutrients. This should encourage any staph bacteria that are present to reproduce and grow.
If the bacteria develop, different antibiotics can be directed at them to see if the bacteria have developed resistance to the antibiotics.
This type of test is often used to screen people before they are admitted to hospital to help reduce rates of MRSA.
Read more about screening for MRSA.
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Treatment
If you have an MRSA infection, you will be given antibiotics that the bacteria have not yet become resistant to.
Most MRSA infections can be treated with the following antibiotics:
- vancomycin or teicoplanin, which are normally given by injection or through a tube straight into your vein
- linezolid, which can be given into a vein or swallowed
You will usually require treatment in hospital. You may be moved to a private room or to a room with others who have the bacteria, to stop the MRSA spreading. Some people will need to continue treatment for several weeks at home.
Visitors
MRSA does not usually harm healthy people. For example, it doesn't harm pregnant women or children, providing they are fit and healthy. Therefore, if you have an MRSA infection, you will still be able to have visitors as normal.
However, it is essential that all visitors wash their hands thoroughly before and after visiting (see MRSA infection - prevention).
Some people are more at risk of MRSA (see MRSA infection - causes). If you have an MRSA infection and someone who is at increased risk wishes to visit you in hospital, you should ask the hospital staff for advice before they visit.
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Prevention
Hospital staff, patients and hospital visitors can take simple hygiene measures to help prevent the spread of MRSA and stop infection.
Hospital staff
Hospital staff who come into contact with patients should maintain very high standards of hygiene and take extra care when treating patients with MRSA:
- Staff should thoroughly wash and dry their hands before and after caring for a patient, before and after touching any potentially contaminated equipment or dressings, after bed making and before handling food.
- Hands can be washed with soap and water or, if they are not visibly dirty, a fast-acting antiseptic solution like an alcohol rub or gel.
- Disposable gloves should be worn when staff have physical contact with open wounds, for example when changing dressings, handling needles or inserting an intravenous drip. Hands should be washed after gloves are removed.
- The hospital environment, including floors, toilets and beds, should be kept as clean and dry as possible.
- Patients with a known or suspected MRSA infection should be isolated.
- Patients should only be transferred between wards when this is strictly necessary.
The aim is to reduce the chance of patients infecting themselves and others.
For more information, the Royal College of Nursing has published MRSA: a guide for nursing staff (PDF, 450KB).
Patients
Hospital patients can reduce their risk of infection by taking the following sensible precautions:
- making sure they have soap, a flannel and moist hand wipes, as well as their own razor
- always washing their hands after using the toilet or commode (many hospitals now routinely offer a hand wipe)
- always washing their hands or cleaning them with a hand wipe immediately before and after eating a meal
- making sure their bed area is regularly cleaned and any unclean toilet or bathroom facilities reported to staff
Visitors
Visitors can reduce the chance of spreading MRSA to other people if they do not sit on the bed and if they clean their hands before and after entering the ward. They should use alcohol gel before touching the person they are visiting.
Dispensers of alcohol gel or hand rub are often placed by patients' beds and at the entrance to clinical areas.
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Screening
Frequently asked questions
Why am I being screened for MRSA?
Many people carry MRSA on their skin or in their nose.
If the NHS hospital can find out if you are carrying MRSA before you go in, it can use a simple treatment to get rid of as much of the bacteria as possible. This means that there is a much smaller chance of you getting an MRSA infection or passing MRSA on to another patient.
When and where will I be screened for MRSA?
Usually you will be screened before you come into hospital for an operation. This may be in a pre-admission assessment clinic, an outpatient clinic, or sometimes at your GP surgery.
Typically, a nurse will take the swabs as part of the other checks, such as blood pressure and a blood test, leading up to your hospital stay.
How will I be screened for MRSA?
NHS staff can find out if you are carrying MRSA by taking a sample of bacteria using a swab. A swab is a cotton bud that is placed on the area of skin to be tested. Swabs may be taken from different places, like the inside of your nose, your armpit or your groin. Swabbing is painless and only takes a few seconds.
When will I get the results from the swabs?
Your swabs will be sent to a laboratory, which tests them for MRSA. The results usually take between three and five days, but may come back the same day.
What happens after I have been screened?
If you are found to be carrying MRSA on your skin or in your nose, you will be contacted by the hospital or your GP. Do not worry if you are contacted, as lots of people carry MRSA. Carrying MRSA does not make you ill and you are not a risk to healthy people. This includes older people, pregnant women, children and babies. A doctor or nurse will let you know what you need to do next.
If you are not carrying MRSA, you are unlikely to be contacted by the hospital or your GP. If you are not contacted, continue with your hospital care as planned.
What happens if I am a carrier of MRSA? If you are carrying MRSA on your skin, you may not be able to have your planned operation or procedure straight away. You may need to be treated for MRSA first to protect you and other patients from getting ill.
What treatment is used to get rid of MRSA from my skin?
Your doctor or nurse will discuss treatment with you. It usually involves using an antibacterial wash or powder and a special cream in your nose.
You may be asked to change your clothes, sheets and pillowcases every day, usually for five days.
You do not need to be in hospital while you are using the treatment. Continue until the day of your operation or procedure or until the five days are complete. You do not usually need to be screened again before you come into hospital.
What if my operation is urgent?
If your operation is urgent and you need to go into hospital quickly, you may be admitted to a side room in the hospital and started on the MRSA treatment as soon as possible.
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Pregnant women
What are the risks of MRSA during pregnancy?
Little evidence is available about the risks of MRSA during pregnancy. However, MRSA does not usually harm healthy people, including pregnant women, children and babies.
If you’re pregnant and have any concerns about MRSA, you can get advice from your midwife or GP. You can also call NHS Direct Wales on 0845 4647.
Carrying MRSA
Some people carry MRSA on their skin or in their nostrils without developing an infection. Some may carry MRSA for a few hours or days, while others carry it for weeks or months.
People may not know that they’re carrying MRSA because it doesn’t harm them and they have no symptoms, unlike people who are infected with MRSA.
There is no evidence to suggest that carrying MRSA during pregnancy can cause miscarriage or harm the unborn baby.
MRSA infection
MRSA can cause infection when it gets an opportunity to enter the body, for example through a break in the skin. MRSA infections are most common in people who are already in hospital because people who are ill are more vulnerable to infections.
MRSA infections in pregnant women are rare. If a pregnant woman does become infected with MRSA, her symptoms will be treated. It is possible for an MRSA infection to pass from the mother to the baby during childbirth but this is also rare. It can happen if there is a wound infected with MRSA in her perineum (the area between the vagina and the anus).
If a newborn baby is infected with MRSA, the infection can be treated in hospital in a special care unit.
Screening for MRSA
Pregnant women in the UK are not routinely screened for MRSA. However, screening may be recommended:
- before a planned caesarean, or
- where there is a high risk of complications for the mother or baby, for example if the baby is likely to need treatment in a special care unit.
Screening may also be recommended in other cases, for example if a woman has stayed in hospital during the previous three months.
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