What is MRSA?

MRSA stands for Methicillin-Resistant Staphylococcus Aureus. It is a form of the bacteria, Staphylococcus aureus (Staph aureus), which has become resistant to standard antibiotics – including the antibiotic methicillin. It is often referred to as a ‘superbug’ due to its ability to resist treatment.

Staph aureus is a common and normally harmless bacteria, which up to a third of healthy people carry on their skin or in their nose without even realising it. Many people also carry the resistant form of the bacteria, MRSA, without experiencing any ill effects. It is only when these bacteria get inside the body – for example, through a wound or surgical incision, that they cause infection.

MRSA is no different from normal Staph aureus in terms of its effects and how it can be spread. The only difference is that normal Staph aureus infections can be treated much more easily. In people with normal Staph aureus, standard antibiotics can be used to kill the bacteria. However, if the bacteria is MRSA, this means that it has developed resistance to antibiotics and is harder to kill.

Why do bacteria become resistant?

Staph aureus has become increasingly resistant to a number of different antibiotics over the past 50 years or so. This is mainly due to the overuse of antibiotics and people not taking their antibiotic medicine properly.

Bacteria are living organisms that are able to change and evolve very quickly in order to adapt to their environment. When a person is given an antibiotic, many of the bacteria are killed straight away. However, others undergo a mutation (change in their genetic material), which allows them to adapt and resist the antibiotic.

If a course of antibiotics is not finished, not all of the bacteria are killed off. This allows those bacteria that have started to develop resistance to persist, increase their resistance even further and to multiply.

Not finishing a course of antibiotics therefore encourages the proliferation of resistant bacteria. Taking antibiotics when they are not needed – e.g., for a virus rather than a bacterial infection, also gives more opportunity for resistant strains to develop.

Why is MRSA common in hospitals?

While anyone can carry MRSA, just like anyone can carry normal Staph aureus, an MRSA infection is more common among patients in hospitals because they are more likely to have an entry point for the bacteria to get into their body – e.g., a surgical wound, an iv tube or a catheter. People in hospital are also more likely to be elderly and to have a weakened immune system due to their illness/injury – putting them at higher risk of contracting an infection.

Not only are patients in hospitals at more risk from MRSA infections than the general population, but hospitals also provide an ideal environment for the spread of MRSA. This is why there has been so much focus on ‘dirty hospitals’ and the importance of hygiene in hospitals over the last few years.

MRSA – like any other bacteria – can easily be transferred from people’s hands directly to another person, or also indirectly via surfaces such as door handles, bed rails and linen. MRSA can survive on objects like these, and without proper cleaning, can be picked up by another person – be it a doctor or a patient. Hospital staff attend to numerous different patients throughout the day, giving plenty of opportunity for this cross-infection from one patient to another.

For this reason, there has been a greater emphasis over the past few years on the importance of hospital hygiene and adequate hand hygiene in healthcare workers (i.e., washing hands properly before and after each patient contact).

What happens if I develop MRSA?

As with ordinary Staph aureus, people can carry MRSA without it being harmful. This is called being ‘colonised’ with the bacteria. However, if MRSA bacteria enter the body tissues or bloodstream, e.g., through a wound or break in the skin, it can cause infection in almost any part of the body. These may include minor infections, such as boils or abscesses, or more serious infections, such as infections of the bone, lungs (pneumonia), heart (endocarditis) and blood (septicaemia).

If you are suspected as having MRSA, your doctor will take blood or urine samples, or a swab of the infected tissue to test for the presence of MRSA bacteria. These tests will also show the doctor which antibiotics you are resistant to and what can be used to treat you.

You may be moved into a separate, isolated room in the hospital if you are found to have MRSA, or into a ward with other people who have the infection. You will still be allowed visitors, as MRSA rarely presents a danger to healthy people – however, your visitors will need to ensure they wash their hands thoroughly after seeing you so that they do not spread the germs to others.

How is MRSA treated?

Staph aureus has become resistant to more and more different antibiotics over the past few decades, making treatment of MRSA increasingly difficult.

If you have MRSA, you may need to be treated with a much higher dose of antibiotics over a much longer period. In addition, there are two antibiotics – vancomycin and teicoplanin – that most cases of MRSA have not yet been able to develop resistance to. These medicines are used as a last resort to treat patients who will not respond to other antibiotics. They can only be administered by infusion or injection while in hospital.

Worryingly, there have recently been a number of cases in other countries of patients who have developed MRSA that is also resistant to vancomycin and/or teicoplanin. Scientists are continuing to investigate new antibiotics that can treat these strains of resistant bacteria.

What is being done about the problem in Ireland?

Ireland has been found to have one of the highest prevalence of MRSA in Europe, and has also had one of the greatest increases in prevalence of the bug over the last few years. The Strategy for the Control of Antimicrobial Resistance in Ireland (SARI) was set up in response to the growing problem in 2001.

SARI committees have issued guidelines and initiated campaigns advising Irish hospitals on how to control the spread of MRSA and on the importance of good hand hygiene by hospital staff. SARI committees also work to promote the proper use of antibiotics in the community.

In 2005, the Health Service Executive in this country began carrying out Hygiene Audits of all Irish hospitals, in order to check whether hospitals are complying with hygiene standards. The audit found over 90% of hospitals in Ireland to have inadequate hygiene standards in Nov 2005; however there was significant improvement by the time the second audit was completed in July 2006.

Under a new Hygiene Services Assessment Scheme due to begin in 2007, all hospitals will have to undergo a mandatory self-assessment of hygiene standards every year, followed by an unannounced assessment by an external assessor. The new scheme aims to take a more comprehensive approach to testing levels of hygiene than the previous audits and stipulates that hospitals must have a strategic team co-ordinating hygiene in the hospital and sufficient resources to ensure rigorous hygiene practices.

What can I do?

If you are prescribed antibiotics:

Do not demand or expect to be given a prescription for antibiotics when you visit your doctor.

If you are visiting someone in hospital, make sure you wash your hands thoroughly, before and after your visit. Many hospitals now provide hand hygiene facilities for visitors.

Reviewed: November 10, 2006

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