The Discovery Of Penicillin

Alexander Fleming fortuitously discovered the antibacterial properties of a Penicillium mould in 1928. During the Second World War much use was made of penicillin in the treatment of battle wounds. Between the years of 1943 and 1955, when he died, Fleming received around 172 honours from all over the world.

Penicillin transformed the treatment of many infections. One such infection was Staphylococcus aureus.

Fleming, in his acceptance speech for The Nobel Prize in Physiology or Medicine, gave the portentous warning that using penicillin inappropriately might lead to the development of resistance. Sure enough, resistance to penicillin of strains of Staphylococcus aureus became a major problem in hospitals in the 1950s. This resistance was caused by the selection of strains of staphylococcus that could produce the enzyme penicillinase (a drug destroying enzyme). These penicillin resistant Staphylococcus stimulated interest in developing semi synthetic penicillins able to withstand the enzyme. The first of these, produced in 1959, was methicillin.

Resistance to methicillin of Staphylococcus aureus was detected within a year of the antibiotic appearing on the market.

Hospital-acquired MRSA refers to occurences on the MRSA infection that have been contracted within a healthcare setting. People in hospital are already suffering from a weakened immune system and are particularly vulnerable to MRSA infection.

Controversy surrounding the lack of hygiene in hospitals has brought attention to the heightened risks of catching MRSA whilst being an in-patient. Medical equipment such as catheters can harbour bacteria. Additionally, regular use of antibiotics has, in part, contributed to Staphylococcus aureus becoming Methicillin-resistant, hence MRSA.

Staphylococci can grow as biofilms, which are specialized communities of bacteria that are highly resistant to antibiotics and immune responses. They are remarkably adhesive and can grow on many surfaces, including implanted medical devices such as pacemakers, heart valve replacements and artificial joints. Preventing or inhibiting the growth of such biofilms would dramatically reduce the incidence of staph infections.

A MRSA screening is a process whose purpose is to detect the presence of the MRSA bacteria in patients. MRSA screenings are used primarily on colonised patients and on infected patients after they have been treated, to determine whether any resistant bacteria remains.

At a community level, MRSA screening may help to identify the source of a MRSA outbreak, and at a national level it can help to identify genetic characteristics of a MRSA strain.

MRSA Culture

The most commonly used test to identify MRSA colonisation is the culture. A swab is taken from the patient and is then cultured. Swabs are usually taken from the nose, though they can also be collected from wound sites or skin lesions on people with known MRSA infections. The culture is a definitive test and usually takes one to two days to complete.

When Are MRSA Screenings Performed?

A MRSA screening may be requested when a doctor, health department, researcher or hospital wants to evaluate MRSA colonisation in a patient, family member or group of people within the community. Certain populations in a community whose members have close contact may be tested for MRSA when an increased number of infections occur within their group. Example of these populations include football teams, residents of nursing homes and health care workers. Sometimes patients who have previously been treated for MRSA will be screened to determine whether the bacteria is still present.

MRSA Screening On Admission To Hospital

To cut down the number of hospital acquired MRSA infections, some hospitals have introduced a screening process that takes place when patients are admitted. Additionally, healthcare workers and family members of carriers may also be screened for MRSA.

It can all begin with something so simple such as a shaving cut. The MRSA organism may have been living on that person for some time, with no symptoms being demonstrated. However, once that shaving cut appears, the bacteria can enter the bloodstream. Then MRSA becomes much more serious.

The MRSA Superbug Enters the Bloodstream

Once SA bacteria is able to enter the bloodstream, almost any part of the body can be affected. The bacteria can cause:

• Septicaemia (blood poisoning) – the type of MRSA infection with the highest death rate;
• Lung infection (pneumonia);
• Septic shock;
• Bone marrow infection (osteomyelitis);
• Inflammation of the tissues that surround the brain and spinal cord (meningitis);
• Infection of the heart lining (endocarditis)
• Severe joint problems (septic arthritis);
• Internal abscesses.

At this stage MRSA can become fatal in about 10 – 20% of cases. Incidence of MRSA, although declining slightly according to government statistics, have increased substantially over the past decade. In 1993, the superbug caused 51 deaths. In 2005, the figure was 1,629.

Why the MRSA Superbug is so Dangerous

The MRSA superbug is able to survive treatment by antibiotics such as methicillin and penicillin. This becomes particularly dangerous in the case of hospital MRSA, because it affects patients with already compromised immune systems. Patients from intensive care units, burns units, surgical and orthopaedic wards are particularly at risk.

The Role of the Media and the MRSA Superbug

It is not the case that coverage of the MRSA superbug is simply ‘news hype’. Nevertheless, the media does not always present a balanced report and viewers do not necessarily remember the critical points. About 30% of the entire population are MRSA carriers of (or colonised with) SA bacteria. Most do not develop an infection and therefore most do not demonstrate any symptoms. The bacteria can be found everywhere – telephones at work, elevator buttons, office pc keyboards, clothing.

The media tend not to report on the relatively harmless community-acquired MRSA that affects younger and otherwise healthy people. MRSA rarely presents a danger to the general public but this does not seem to be the media interpretation. The media focuses on where the deaths are – hospital-acquired MRSA, ‘killer MRSA and VRSA’.

The ‘Killer’ MRSA Superbug

A rare mutation of CA-MRSA produces the lethal toxin panton–valentine leucocidim (PVL). PVL destroys white blood cells, destroying a person’s immune system and leaving it too weak to fight infection. Pneumonia, very high temperature and coughing up blood are all symptoms. Alarmingly, only a quarter of victims survive PVL if it spreads to the lungs.

The VRSA Superbug

VRSA is Vancomycin-resistant Staphylococcus aureus. It is a rare strain of MRSA that is resistant to Vancomycin, the drug of last resort. Vancomycin is used to treat MRSA when other drugs have failed (see  Vancomycin and MRSA). The unnecessary overuse of antibiotics over a number of years is believed to be responsible for the bacteria’s resistance. The presence of VRSA does not signal death however. Oral drugs such as Linezolid, Doxycycline or Minocycline can be used.

MRSA Superbug: In Summary

The MRSA superbug is very serious but news coverage tends to focus on the death-related incidents where the superbug has entered the bloodstream and does not always present a balanced picture. Most of the 30% of the population who are colonised with SA bacteria, will show no symptoms. News coverage focuses on hospital MRSA, ‘killer‘ MRSA and VRSA, the latter two being extremely rare. Despite public perception, MRSA can be serious but in the majority of cases, is by no means incurable.

Superbug Test Now Available in Europe

A test for detecting the superbug MRSA is now available in the European Union. Improved MRSA screening for methicillin-resistant Staphylococcus aureus (MRSA) should result with the introduction of this new test. The international drug developer Roche has claimed that the new test will help to prevent and control infections.

Hospital To Screen Patients For MRSA

Screening for MRSA will be offered to patients in East Surrey before planned operations, to try to combat the spread of the superbug. Swabs will be taken from patients’ noses before the operation to check for MRSA at East Surrey Hospital Redwood Elective Centre and Crawley Hospital.

Zero Tolerance Battle With Superbug

At the Chesterfield Royal Hospital, hospital matrons have launched a MRSA screening programme for all patients undergoing pre-booked surgical procedures in an attempt to reduce the risk of infection.

‘High risk’ patients have always been screened for MRSA at the Chesterfield Royal Hospital. However, now the pre-admissions clinic is checking everyone admitted for an elective (pre-booked) procedure. This is one more component part in the struggle to combat MRSA and should not be viewed in isolation.

The screening system is part of a nationwide initiative brought in by the Department of Health and supports the hospitals programme of infection control, which includes a hand hygiene and cleaning regime.

If a patient is carrying MRSA they can be given treatment that will significantly reduce the risk of infection. As an infection, MRSA causes boils, infected wounds, abscesses and infections of the chest, bloodstream and urine and, ultimately, can be a killer.

A swab will be taken from the patient’s nostrils or groin and sent off to Microbiology for testing. If it returns positive, they will be given treatments – an antibiotic nose cream and skin wash – to use at home for five days before their procedure.

As a result of the Chesterfield Royal Hospitals proactive approach it is one of the top performers in the country for MRSA rates.

Patients ‘Swabbed’ For MRSA

At Burnley General Hospital and Royal Blackburn Hospital all patients booked in for an operation are being “swabbed” for evidence of MRSA in out-patient clinics. Patients found to have MRSA are sent an antiseptic body wash and nasal spray to use for five days before their operation. This should reduce the risk of infection.

The Burnley General and Royal Blackburn Hospitals are aiming to reach the Government’s target of giving every hospital patient the test by 2011.

Handwashing ‘More Effective At Controlling MRSA Than Isolating Patients’

Regular hand washing could be more effective at controlling the spread of the hospital superbug MRSA than isolating infected patients. Dr Peter Wilson from University College Hospital, London, led a study, which examined two ICU wards over the course of 12 months.

Dr Wilson argues that the best way to halt MRSA is to ensure that staff keep their hands clean. This is not to suggest that isolation should not be considered as an option. It does however re-emphasise the importance of hand washing as part of the very core of the strategy to combat MRSA

Keep up to date with MRSA News.

Defining Community-Acquired MRSA

A community-acquired MRSA infection is an MRSA infection in an individual who has had:

• MRSA identified within 48 hours of admission to a hospital
• No history of hospitalisation, surgery, dialysis, or residence in a long-term care facility within 1 year of the MRSA culture date
• No permanent indwelling catheter or medical device
• No known prior positive culture for MRSA.

It should be noted that in practice it is difficult to separate true community-acquired MRSA from MRSA that people out in the community may have acquired from a healthcare setting, or from close contact with a person in a healthcare setting.

Community-Acquired MRSA – The Basics

MRSA infections are usually associated with hospitalisation or other healthcare-associated risk factors. More recently however, physicians and other healthcare providers have observed an increasing number of people with MRSA infections who seem to lack traditional healthcare-associated risk factors. It appears that these people have community-associated infections. Skin and soft tissue infections such as abscesses or cellulites are the most common kind of infection caused by Staphylococcus aureus.

The incidence of community acquired MRSA infections is greater amongst younger and healthier people compared with healthcare-associated MRSA. CA-MRSA bacteria is generally less problematic than healthcare-associated MRSA and is usually susceptible to more types of antibiotics.

Identifying Community-Acquired MRSA

CA-MRSA most often appears as a skin or soft-tissue infection. This could be a boil, pimple, or abscess, in an otherwise healthy person. The area in question often becomes red and swollen. It maybe painful and have pus or a discharge. A person should pay particular attention to any cuts and scrapes and hairy areas of the body, such as the back of the neck, groin, buttocks, armpits, and the inner thigh.

Although community-acquired MRSA is relatively harmless in some cases it has been associated with more serious conditions. CA-MRSA has been associated with necrotizing pneumonia and empyema; sepsis syndrome; musculoskeletal infections, such as pyomyositis and osteomyelitis; necrotizing fasciitis; purpura fulminans; and disseminated infection with septic emboli.

At its extreme community-acquired MRSA has resulted in death. Ten years ago four children in Minnesota and North Dakota were reported to have died from CA-MRSA infections. It should be stressed however; in the vast majority of cases CA-MRSA does not cause life-threatening conditions and can usually be dealt with speedily and effectively. Measures should be taken to prevent the spreading of CA-MRSA and therefore we must understand how it is passed from one individual to another.

The Spreading of Community-Acquired MRSA

CA-MRSA infections can be spread by contact with infected skin or personal items that have been in contact with infected skin such as towels, bandages, or razors. The bacteria get into the skin through cuts. Bacteria are more likely to spread where there is close contact between people. Outbreaks have been reported in football, wrestling, rugby, soccer, fencing, canoeing, prison inmates, and the military. There have also been CA-MRSA cases in tattoo recipients.

Community-Acquired MRSA: In Summary

A clear distinction is made between CA-MRSA and healthcare-associated MRSA. However, ensuring that CA-MRSA patients really do not have any link to a healthcare setting is often quite difficult.

CA-MRSA tends to affect a different section of the population – younger and healthier people compared to hospital MRSA. In most cases, CA-MRSA is also easier to treat.

Care should be taken in environments where there is close contact between people to prevent the spread of CA-MRSA. It should be stressed however, it is very rare for CA-MRSA to result in a serious or life threatening health condition.