The Background And Significance Of MRSA Infection

Infection disease acquired in hospitals have changed during the past decades, Gram-negative pathogens were predominantly responsible. However serious infections were brought under control with the discovery of penicillin, but as resistance to antibiotics spread new and dangerous superbug strains emerged. The main infective threat on the increase in micro-organisms that is resistant to many antibiotics is Methicillin-resistant Staphylococcus aureus (MRSA), (Abb, 2004). Aims of this essay:

The Background and significance of MRSA infection.

Critically Review Epidemiology of MRSA.

Explore MRSA Screening/programmes in both hospital and community.

Critically analyse Ethical implications of introducing MRSA Screening.

MRSA was first discovered in 1961, during the time in the UK when almost all people were having significant health care through the National Health Service. MRSA was first recognised as a source of infection which then became a major nosacomial pathogen transmission within the hospital and in the community. Infections due to Staphylococcus aureas are a growing clinical and a public health problem globally, and the incident of patient infection and colonisation of MRSA continues to rise in the UK health-care system. Delano et al (2000) described MRSA as a major nosacomial pathogen, with transmission within hospitals, transmissions between different hospitals, hospitals within the same country and even intercontinental spread of endemic strains. However certain strains could be found worldwide and only few strains were responsible for a large part of MRSA infections, (Boyce et al, 2005). Germany saw the proportion of MRSA to S. aureus in clinical specimen rise from 8 % in 1995 to 30 % in 2003 – a higher increase than in nearly all other European countries, (Robinson and Enright, 2004).

Community-associated MRSA (CA-MRSA) infections have turned out to be the most troubling pathogen. Its increase in the community has reported infections among healthy children and adults. But little remains unknown about how patterns of colonisation with MRSA in the community have changed, (Health Protection Agency, (HPA), 2004). An epidemiology report stated that each year around 1 in 10 NHS patients contract a healthcare associated infection (HAI) in the UK (Department of Health, 2003). In Scotland, HAIs were recorded as a major factor in an estimated 457 deaths each year and a contributory factor in a further 1,372 deaths 3% of all deaths, DoH (2003). Therefore the economic burden of HAI to the hospital sector was substantial, with the annual cost to the NHS estimated to be £186 million in Scotland (Walker, 2001) and in excess of £1 billion in England and Wales Plowman et al, (1999). MRSA has been is identified by (Boyce et al, 2005) as the major cause of hospital associated infections, causing skin and soft tissue infections, pneumonia, bloodstream infections, and bone and joint infections in both children and adults. The Health protection Agency verify that once acquired, MRSA has the potential to cause multiple infections, for cardiac surgery patients, sternal wound infection can lead to mediastinitis, infection of the heart valves or endocarditis. The lethal MRSA strain known as USA600 which causes bloodstream infections has been known to be five times more lethal than any other strains. Research conducted by Henry Ford Hospital study claims that this strain has some resistance to the potent antibiotic drug vancomycin used to treat MRSA, and its unique characteristics have been linked to high mortality rate. However, Chastre and Trouillet, (1995) argues that all MRSA strains have significant mortality risk, with this strain it is unclear whether other factors such as older age, diseases or the spread of infection contributed to poor outcomes. The latter adds that MRSA colonisation and infection is now considered endemic within hospitals in the UK, with critical care and regional units being recognized as high-risk areas. (Coello et al, 1997) is in agreement stating that intensive care patients are known to have a higher risk of developing MRSA infection than medical patients. This could be due to their association with the frequent use of broad-spectrum antibiotics or the increased transmission risk because of frequent contact with many personnel (Haley et al, 2002). Risk factors include: previous hospitalization; underlying disease, surgical wounds; intravascular lines; recent antibiotics (leading to potential suppression of the immune system); and pressure ulcers (Ayliffe et al,1998).

Managing these patients proves to be very difficult and costly due to problems associated with treating systemic MRSA infections, its propensity to spread and colonize debilitated patients, and its asymptomatic carriage in the nose and throats of staff and patients, (Ayliffe et al, 1998). Treating systemic MRSA infection needs extensive antibiotic therapy; the need for the patient to be nursed in isolation; an extended length of stay and a severely unwell patient who is then further compromised. The risk of death in patients with RSA is three times greater than other hospital-acquired infections (Romero-Vivas et al, 1995). As well as increasing morbidity and mortality, MRSA infection is expensive. Costs can be divided into those related directly to the effects of the infection, such as extended length of stay, pharmacological intervention and other aspects of management, and expenses related to the cost of controlling the infection. Then major threat facing the UK health care system is the MRSA transmission in the community among individuals who had not been in hospital previously, or had had any contact with a person who had been in hospital or care homes, previously would have explained how they contracted the bug. With the increase of community acquired MRSA (CA-MRSA) this would prove to be a huge problem, because some infected people will inevitable be hospitalised themselves, or visit relatives and friends who are in hospitals. Therefore an increment in outbreaks of new types of MRSA strain, (Boyce et al, 2007). Barr et al (2007) claims that the community strains are different from the hospital strains, he believes that the community strains have evolved independently and so they present a whole new series of problems for control and treatment. The aim of this write up is to discuss MRSA screening; how screening patients can prevent the spread of MRSA; the prevalence and incidence of MRSA in the UK, a critical epidemiology of MRSA will be discussed with the inclusion of ethical implications on screening.

Epidemiology of MRSA

MRSA is an epidemiological problem, which can have its source in the community and health care settings, the epidemiology, of MRSA in relation to agent, host, environment, web of causation and its natural history. The National Audit Office 2004 report shows that figures collected from the DoH’s own mandatory reporting system had indicated 8% increase in MRSA incidences between 2000-2004. The 2004 report figures almost reaching 20.000 infected patients. Therefore this made the rate of infection in England the worst amongst Europe, (Cuevas et al 2004). However other sources quoted the UK infection rate as being 30,000 hospital acquired infection per year, (Morton et al 2003), which they quote as infection representative of a 9& infection rate. The latter continue to claim that 5000 will die, but it is important to make the distinction that the authors did not suggest that 5000 will die, they will do so as a result of the MRSA infection.

MRSA is a skin bacterium that is resistant to many antibiotics. It can colonise the skin, however colonisation itself does not cause illness, (Timbury et al, 2002). Colonisation in vulnerable patients may precede infection that may be severe and life threatening. A high percent of 20-30%.of population may carry MRSA a Gram positive bacterium as their normal skin organisms, (Cooper et al, 2003). The latter, further state that the infections MRSA cause, are not considered more serious than those caused by Meticillin sensitive can be more difficult to treat. MRSA is a virulent bacterium that can cause serious infections of the skin. It can be introduced into the body through broken skin, insertion of a device or an invasive procedure. Once within the body it can cause a range of illnesses from relatively minor localised skin and wound infections, such as boils, to systemic life threatening infections such as endocarditis, pneumonia and bacteraemia (Cooper et al, 2003. Meticillin is an antibiotic previously used to treat infections; however it is now replaced by Flucoxacillin from the same group of antibiotics. Flucloxacillin is known to be very effective antibiotics for many common infections including those caused by MRSA. However there is an increasing emergency of strains of MRSA that have developed resistance to antibiotics such as Flucloxacillin.

MRSA has developed resistance by mutation of the penicillin binding site in the bacterial cell wass so that the antibiotic no longer attach itself to its target, making such strains resistant to all penicillin’s and cephalosporin antibiotics. Unfortunately MRSA also often acquires resistance to other antibiotics making it multi-resistant. Treating infections caused by resistant bacteria require the use of more complex antibiotics, some of which can only be administered intravenously. It is important that the use of these antibiotics is reserved for more serious infections; resistance can emerge during therapy, especially if prolonged,

The prevalence of MRSA transmissions has steadily increased in hospitals and in care homes in the UK and Globally. The centres for disease control (CDC) in the United States, claims that’s in the mid 19890s MRSA was mainly limited to relatively large urban medical centres and the rates where smaller with the prevalence rates of 50% to 10%. However by the 90s rates among the community hospitals increased to 20%, (Klevens et al, 2007).

Because no systemic, population-based surveillance of community isolates of MRSA, the true prevalence of MRSA cannot determined. However one study found that up to 40% of MRSA infections in adults were acquired before admission to hospital. However published reports on MRSA colonisation and infection among study participates who lack traditional risk factors indicate that community prevalence rates are rising., ( ). The incidence of community-associated MRSA has risen dramatically in the UK, particularly among children. ( ), suggest that there varying evidence suggesting there appears to be different MRSA strain found in the children within the community setting. The epidemiologic features described appear to show a major departure from features typically associated with MRSA colonization or infection. Young children tend to have higher colonisation rates, probably because of their frequent contact with respiratory secretions, ( ). Although Streptococcus pneumonia colonization has been inversely associated with MRSA colonization in unvaccinated children, this and other risk factors for MRSA carriage have not been assessed following widespread use of the heptavalent pneumococcal conjugate vaccine (PCV7), ( ). Colonisation may be transient or persistent and can last for years, ( ).

( ), MRSA infection presents a serious epidemiological problem because not only are new strains appearing but also a number of nasocomial MRSA infections are known to have their source in the community setting, which causes the route of transmission to remain a mystery. ( ), claims that the CA-MRSA are unlike the hospital strains which typically are resistant to multiple antibiotics, but the community strains have tended to be susceptible to other antibiotics classes and often are resistant only to beta-lactam antibiotics. It appears that the origins of community acquired strains are subject to debate, some suggesting they are feral descendants of hospital isolates (Alvina, 2008). If these are isolate then they must have undergone considerable change, because they possess distinctive PFGE patterns and have lost hesitance to multiple antibiotics.


Screenings is a way to identify health issues, those at risk or are already affected by, a disease or its complications. Dr Angela E Raffle , a Consultant in Public Health , suggested that they are types of screening that can do more harm than good however, to be screened is to people who think or feel they are healthy to find if they have certain health problems or risk factors they did not know about before. However an opportunity for education for health arise, screening can be used as tool to mobilise community group or individual action one the individual has their screening results it is up to each individual on how to change his or her health behaviour or even encourage to maintain positive behaviours. Therefore screening can be used in a way which helps to motivate and support people to develop skills and to make decisions, collectively or individually, which are right for them. Used in this way screening becomes an effective health promotion.

They are various types of screening which include: Whole-body computerised tomography (CT) screening (a sophisticated kind of x-ray), the implied promise is that it can either find disease and lead to better outcome because of early recognition, or it can give important reassurance that you are healthy. Whole-body magnetic resonance imaging (MRI) screening, although there is no radiation dose, the usefulness of this as a screening procedure is completely unproven.

There are good public health reasons for screening certain populations, or sub-populations. However, one need to think carefully about the role of screening and whether the time, energy and money involved are justified, and the fact that screening can intrude into people’s lives and invade their privacy. However MRSA screening is for the benefit of both the individuals and the rest of the population in hospital or out in the community. Early identification of patient with MRSA and subsequent prevention of patient to patient spread through infection control measures is believed to be important interventions to control MRSA. Experts and policy makers, nationally and internationally recommend universal MRSA admission screening. However no controlled trails have tested the hypothesis that rapid screening may improve patient outcome by decreasing MRSA cross transmission and increasing the adequacy of pre-operative prophylaxis. DoH operational guidance (July 2008) states that all elective admissions must be screened by April 2009 and that all admission including emergencies admissions.

In view of high levels of MRSA prevalence in the UK health care system, from April 2009 the Doh implemented the MRSA screening on all patients electively admitted to the hospitals. The requirement extended to emergency admissions. The stringent measures introduced by the DoH to reduce the burden of infection associated with MRSA, with success numbers of MRSA bloodstream infections appear to be falling by more than half from 2003 to 2008, Muller (2008). However the overall numbers of healthcare associated infections reported to the English health Protection Agency rose substantially, raising question about the focus on MRSA argued, (Donalds 2006). Before April 2009 most NHS trusts screened patients for MRSA when they were considered to be at high risk of MRSA colonisation or infection. However the mandatory MRSA screening policy extends the range of individuals screened to include people at low risk of MRSA colonisation or infection, such as patients without serious comorbidity admitted for hernia repair or arthroscopy. The policy runs contrary to current UK guidelines for the control of MRSA, which emphasise selective screening, (Muller, 2009) and to US guidelines, which do not support legislation to mandate MRSA screening, Bonita et al (2000). In the UK, hospital admission is the main risk factor for acquiring MRSA, and invasive medical procedures (particularly placement of a central venous catheter) are the biggest risk factor for MRSA bloodstream infections, (Pugliese and Favero, 2004). This is clearly a matter of debate, research claims that more infected people are found in the community and some do not appear to have had any contact with the hospital, the statement above needs more evidence to back it up. The evidence supporting screening even in high risk groups is largely derived from uncontrolled studies. A large controlled study in a Swiss surgical unit reported no benefit from screening on admission. The Department of Health’s impact assessment of universal MRSA screening assumes that everyone screened has an equal risk of infection.

Preadmission screening was extended to all patients who were due to have surgery. Long-term patients, whose inpatient stay was on either the intensive care unit or the ward, were routinely screened. Previously, day case cardiology cases had been excluded from preadmission screening because of the short time these patients stayed in the hospital. The screening comprised skin swabs from the nose, axilla and groin. Increased efforts were employed to ensure that all patients were screened before their admission. Screening was undertaken at the outpatient appointment in the preadmission clinic, via the GP surgery or in the local hospital in the case of inpatient transfers. Before this initiative, all patients had been routinely screened, but this was performed on admission instead of before admission. This led to a situation whereby patients were operated on and moved through several departments before their MRSA status was detected. Referring hospitals were also asked to screen those who required transfer for surgery. If MRSA was detected, or if the status was unknown, the patient was admitted directly into a side-room and nursed in isolation until cleared of MRSA, the negative result was known. The MRSA screening tests have false positives leading to the isolation of patients who are non MRSA positives carriers as well as false negatives missing some carriers. For modelling purposes agar culture of bacteria from swabs was considered to identify MRSA with a sensitivity of 68% and a 6% incidence of false-positive tests. Enrichment broth culture was considered to identify MRSA with a sensitivity of 98% and a 6% incidence of false-positive tests. Real-time PCR was considered to identify MRSA with a sensitivity of 92% and a 9% incidence of false-positive tests.

Patients colonised or infected with MRSA should whenever possible be placed in a private room, or housed with other patients who have MRSA, (British Society for Antimicrobial Chemotherapy). The effectiveness of this widely accepted policy has not been proven in randomised trials, (Grundmann et al 2006. However in a systemic review, Cooper and co-workers, (Coopers et al, 2004), concluded that patient isolation, when combined with other control measures could reduce the spread of MRSA. Guidelines recommend that healthcare workers wear gloves when caring for MRSA-positive patients and that gowns be worn when substantial contact with patients or their environment will occur, (Coia et al, 2006). Nonetheless, Pittet et al, (1999) suggest that effectiveness of the use of gloves and gowns to care for patients with MRSA has not been established in randomised trails, although epidemiological studies support their use. Boyce et al (2002) claims, that as part of major nursing based procedures, hand washing has a vital part to play. They go on to claim that is is probably regarded as the gold standard, because all the articles on the subject they reviewed suggested hand washing. The lack of evidence of an effect associated with specific measures should not be mistaken for lack of effect, (Cooper el 2004). It can obviously be argued , that this is largely be due to the fact that although there have been a number of trails on the subject ethical and practical difficulties involved has proved far from easy to get a good evidence base in this area (Muto et al, 2003).

Ethical Implications

The Department of Health’s impact assessment does not mention the consequences of the mandatory screening policy on patient isolation, even though its best practice advice is that patients with MRSA colonisation or infection should be isolated if possible, Wyllie et al (2005). As well as adversely affecting the patient, isolation may affect control of other infections because it reduces the availability of isolation rooms. Thus MRSA screening of low risk patients is of uncertain benefit and may do harm. The issue of consenting to a screening test and the subsequent management of a patient found to be MRSA colonised is primarily an ethical one. There is no published literature referring specifically to the ethics of screening for MRSA and principles were, therefore, extrapolated from work on other conditions Krantz et al (2004). Ethical considerations include the right of the individual to make an informed choice, the balance of benefit over harm and general fairness. The objective of MRSA screening is to protect all vulnerable individuals within the hospital, rather than simply preventing infection in the individual being screened. A comprehensive ethical model must include the concerns of both the individual and public health, and consider all groups affected: those offered screening, other patients susceptible to MRSA infection, staff and policy makers. The concept of justice or general fairness demands that all patients are treated in the same manner, irrespective of their social or economic status. Selection for screening and subsequent MRSA colonisation management should not be influenced by these factors, and provision of patient information should recognise variations in levels of understanding.

The balance of benefit and harm associated with MRSA screening is most complex for those being offered screening. The actual MRSA screening test, be it carriage assessment or swabbing, is extremely low risk in terms of direct harm. However, those offered screening may become anxious regarding their test result or, alternatively, could be reassured by the efforts of the hospital to limit MRSA transmission. Those patients subsequently found to not be colonised should also be reassured by this fact. Patients colonised with MRSA may feel stigmatised and reactions to the use of contact precautions or isolation can vary. Concerns expressed in the literature include the possibility that patients in single-bed rooms or isolation: receive poorer quality care as a result of limited contact with healthcare staff,

experience restrictions in accessing other hospital areas and receive less stimulation. In addition, the patient’s subsequent placement in the community could be hampered by MRSA colonised status. However, the privacy of a single room can be viewed positively by patients (Dent & Dent, (2005).

When the patient is at risk of infection, for example due to an imminent surgical procedure, knowledge of their MRSA colonisation status allows measures to be taken to reduce their risk of developing an infection. This may delay the patient’s admission or procedure, while decolonisation is carried out. For individuals at high risk of becoming colonised with MRSA the screening of others does not cause harm but is beneficial, once actions are taken to minimise spread. For staff and policy makers the balance is between the benefits of preventing MRSA infection and reducing its overall prevalence, and the negative aspects of a resource intense screening strategy. The principle of autonomy implies that the individual has the right to refuse treatment. For MRSA screening, there is a conflict between allowing the individual the right to choose to not be screened and the rights of vulnerable others. A patient refusing to be screened can be managed as if testing MRSA positive, but will be subject to some negative factors associated with MRSA colonisation. It is important that both patients and staff understand the reasons for MRSA screening, including the uncertainties surrounding any screening process. Good quality information can reduce the anxiety generated by a screening test and fulfil the requirement for informed consent. The manner in which such information is imparted and the quality of care given to those requiring isolation are important and may influence an individual’s willingness to participate in screening. The legal consequences of any litigation following acquisition of MRSA infection in hospital could be altered by knowledge of whether the patient was or was not colonised at the time of admission. Studies in England and Scotland have suggested that up to 1 in 4 hospitals MRSA bacteraemia cases are diagnosed within 48 hours, indicating that the individual had been incubating MRSA on admission (Ferguson et al (2005).


Clinical effectiveness assessment identified a large body of literature on MRSA. However most publications reported on observational studies, infection outbreaks or routine information collection and, as a result, the literature base was considered methodologically weak. The following findings were used to support cost effectiveness analyses: • the incidence of MRSA colonisation amongst patients admitted to acute inpatient care in the UK is not known. Given the restricted data, the results of an ongoing study screening patients admitted to a UK district general hospital and citing an MRSA prevalence of 7% were selected for the economic model. However, several factors such as nurse-to patient ratios and low hand-hygiene-compliance rates could have made detection of a difference in transmission rates difficult during the trial periods. Health-care workers who are nasal carriers can serve as sources of MRSA transmission, although they are not nearly as important a reservoir as are colonised or infected Patients. Because nasal colonisation of health-care workers can be transient, recovery of an outbreak or endemic strain from a health-care worker on one occasion does not provide convincing proof that they have transmitted the organism to patients, ( ).