MRSA FAQs

Staphylococcus aureus is a bacterium that is commonly found on human skin and mucosa (lining of mouth, nose etc). The bacterium lives completely harmlessly on the skin and in the nose of about one third of normal healthy people. This is called colonisation or carriage. Staphylococcus aureus can cause actual infection and disease, particularly if there is an opportunity for the bacteria to enter the body eg via a cut or an abrasion.

Staphylococcus aureus causes abscesses, boils, and it can infect wounds -- both accidental wounds such as grazes and deliberate wounds such as those made when inserting an intravenous drip or during surgery. These are called local infections. It may then spread further into the body and cause serious infections such as bacteraemia (blood poisoning). Staphylococcus aureus can also cause food poisoning.

Infections caused by many antibiotic-sensitive varieties of Staphylococcus aureus are usually successfully treated with antibiotics such as some types of penicillin and erythromycin. Some S. aureus bacteria are resistant to the antibiotic methicillin, and they are termed methicillin-resistant Staphylococcus aureus (MRSA). They tend to be more complicated to treat and require the use of other antibiotics. We are lucky in the UK that the MRSA that infect patients are usually more sensitive to antibiotics than in some other parts of the world.

MRSA stands for methicillin-resistant Staphylococcus aureus. They are varieties of Staphylococcus aureus that are resistant to methicillin (a type of penicillin) and usually to some of the other antibiotics that are normally used to treat Staphylococcus aureus infections. There are different types of MRSA and the Health Protection Agency is able to carry out laboratory testing to distinguish between them.

It is not generally necessary to treat MRSA colonisation or carriage. MRSA infection is no more dangerous or virulent than infection with other varieties of Staphylococcus aureus , but it is more difficult to treat depending on whether it is resistant to any other antibiotics. Some of the antibiotics used to treat MRSA however can on occasion be more difficult to use or may cause side effects.

MRSA infections usually occur in hospitals and in particular to vulnerable or debilitated patients, such as patients in intensive care units, and on surgical wards. Some nursing homes have experienced problems with MRSA. MRSA does not normally affect hospital staff or family members (unless they are suffering from a severe skin condition or debilitating disease). In general, healthy people are at a low risk of infection with MRSA.

MRSA are one of the most prevalent micro-organisms involved with healthcare-associated infections worldwide. Most patients who are colonized with MRSA do not go on to develop an infection. The surveillance of MRSA in the UK is a mandatory scheme run by the Department of Health and measures the number of blood-stream infections reported by Acute NHS Trusts. The latest data for this shows there were 3,517 reports between October 2005 and March 2006 (for further information see the mandatory surveillance report 2006).

MRSA strains were first seen in many countries in the 1960s, but new strains appeared in the 1980s, which have caused outbreaks of infection in hospitals throughout the world including the UK. Further new strains also emerged during the 1990s.

The rise in MRSA infections in the UK is likely to be multi-factorial. The new strains that emerged in the 1990s may be more virulent (i.e. more likely to cause infections) than some of their predecessors, or more easily spread on the hands of healthcare workers, equipment, and perhaps via the environment. There are also a number of factors that aid in the spread of MRSA in hospitals such as: patient transfers within and between hospitals, the increasing number of very ill patients seen in hospital and the difficulty in isolating some patients with MRSA. The increasing complexity of healthcare and medical intervention also add to the risk of acquiring MRSA.

Several studies have shown that workloads are also an important factor: the more the required number of hand hygiene measures needed per hour the less the compliance. This is why rapid acting alcohol and other hand hygiene solutions are now advocated in healthcare: they are easier and faster to use.

MRSA is most commonly spread via hands, equipment, and sometimes the environment. It is important that healthcare workers and visitors wash their hands before and after visiting a patient. Provided hands are not soiled (when they should be washed with soap and water), rapid acting alcohol and other hand hygiene solutions are now advocated in healthcare: they are easier and faster to use than hand washing. Equipment should also be cleaned after use.

There will be precautions put into place to prevent the spread of the organism from patient to patient. Ways of limiting the spread include hand washing, cleaning equipment after use and keeping the environment clean. The hospital may need to move the patient into a single room, or in with other affected patients, to reduce the risk of spread to another patient. Each hospital will have a policy on how to best manage MRSA within their local environment.

Hospital strains of MRSA do not normally cause harm to healthy people, including pregnant women, children and babies. Visitors should ensure they wash their hands before and after visiting the patient.

Some people carry MRSA most commonly in the nose and occasionally on the skin without it causing harm to themselves or others. This is known as colonisation or carriage. When a person has an MRSA bacteraemia (bloodstream infection) this means that MRSA has gained access to tissues and bloodstream and is multiplying and causing harm. MRSA rates are measured by dividing the number of patients with MRSA isolated from blood specimens in a hospital by the activity level within the hospital which provides a 'rate'. This enables one hospital to gauge itself against other similar hospitals and investigate possible causes for differences.

Carriage of MRSA should not be a reason for stopping admission to hospitals, nursing or residential homes or for discharge to their home. However sometimes hospitals screen upon admission eg for planned elective surgery. This enables treatment eg special washes or ointments to be given to reduce or clear MRSA before surgery.

If equipment and wards are not cleaned properly there is a possibility of a contaminated environment contributing to the spread of infection. However dirty areas of hospitals do not necessarily have high MRSA rates or, clean ones low MRSA rates.

Good hygiene particularly in the form of simple everyday precautions such as hand washing is an effective method in the prevention of MRSA spread. If cutlery and plates are washed using soap and water (preferably hot) this will remove MRSA. The risk of acquiring MRSA through contact with curtains, sheets and cushions etc is very low.

Thorough hand washing and drying between caring for people, and whenever necessary, has been shown to be the single most important measure in reducing cross-infection. Healthcare workers use antiseptic solutions, including alcohol hand rubs. More recently, many hospitals have alcohol gels for hand cleaning at the end of patients' beds. The environment must be kept clean and dry. Whilst in hospital, patients may have to be nursed in a special ward and visitors may be asked to wear gloves and aprons. Before going home visitors may be advised to wash their hands.

Various research initiatives are underway from the design of hospital wards, the use of isolation rooms, to the effectiveness of interventions like Clean Your Hands Campaign and investigation of the causes of multi-drug resistance. The Department of Health has also set aside £3 million for research as part of implementing Winning Ways, the Chief Medical Officer's action plan to reduce healthcare associated infections.

Community-acquired MRSA infection (C-MRSA) is when an MRSA infection occurs in a previously healthy individual who has no recognised risk factors associated with MRSA - for example, no previous hospitalisation, surgical procedures or prolonged antibiotic treatment. In the UK, the term community-acquired MRSA may refer to infections in residential homes caused by hospital strains of MRSA However, some other countries (eg United States) are describing strains of MRSA that have arisen in the community ('true' community MRSA) and are very different from hospital MRSA strains. Some of these strains carry a toxin called Panton-Valentine Leukocidin (PVL). These usually affect otherwise healthy people and are unusual in the UK.

Yes, 'true' C-MRSA infections are different from the hospital acquired MRSA, notably C-MRSA is more sensitive to antibiotic treatment than hospital acquired MRSA, and therefore a wider range of antibiotics can be used to treat them.

There have been no systematic studies to establish how common C-MRSA infection is in the UK , but S. aureus isolates referred to the HPA's reference laboratory are routinely tested to identify whether they are C-MRSA. Through this surveillance of MRSA isolates, the Health Protection Agency has identified approximately 100 cases over the last three years.

It is believed that personal contact is the principal risk factor, particularly where the skin is likely to be broken. Investigations in countries that have seen this type of MRSA describe infections in for example in prison inmates, those involved in close contact sporting activities, the gay community, and injecting drug users.

Treatment of C-MRSA infection is easier than for hospital acquired MRSA as C-MRSA are more susceptible to antibiotic treatment. C-MRSA is universally sensitive to the antibiotics vancomycin, rifampicin, gentamicin, and linezolid.

The Office for National Statistics (ONS) provides national statistics on causes of deaths. ONS statistics show that in 2004 in England and Wales, 1168 death certificates mentioned MRSA as a factor contributing to the death of those individuals. In 360 of these individuals MRSA recorded as the main cause of death, in other words a death due to MRSA infection.

This figure is incorrect. It comes from a very rough estimate of the number of deaths which may be attributed to all hospital acquired infections (HAI), not just MRSA. The estimate was made in 1995 by a working group of the Public Health Laboratory Health Service. It used an estimate of the percentage of deaths associated with all HAIs made in the USA in the 1980s (1% of all deaths in the USA). This percentage was applied to the total number of deaths occurring in the UK, yielding a crude estimate of 5,000 deaths from HAI.

Patients in hospital are more vulnerable to many infections, including those caused by MRSA, because devices such as intravenous catheters, or procedures such as surgery, provide an entry point for germs to enter the body. The most common types of infection caused by MRSA are local infections of the skin that can be treated successfully with proper skin care and antibiotics. Some MRSA infections can become life-threatening. Patients who are at particular risk are those who are seriously ill with another medical condition or whose immune system is weakened by diseases such as diabetes or kidney disease, or by treatments for conditions such as cancer.