Antibiotic resistant superbugs

The term superbug has become frighteningly familiar over the past decade. These bacteria, which have become resistant to the antibiotics used to treat them – in other words, the medicines no longer work – are a major cause of hospital-acquired infections and cost the NHS £1billion a year to tackle.

An estimated 25,000 patients die of drug-resistant infections each year, with the most common, MRSA, slowly being superseded by a raft of new, even more deadly strains.

These have been dubbed hyperbugs and are partly fuelled by the growth of health tourism with patients bringing back new strains from hospitals abroad.

Earlier this year, the World Health Organisation warned that the situation had reached a critical point and said that if no action was taken, ‘the world is heading towards a postantibiotic era, in which many common infections will no longer have a cure and, once again, kill unabated.’

So what are these bugs, how do you catch them and, more importantly, how can they be avoided? Here, DR KIM HARDIE, associate professor in molecular microbiology at Nottingham University, explains what you need to know.

Some superbugs are naturally resistant to antibiotics, but in other cases they have undergone changes to enable them to survive.

Mutations (changes) in the genetic code of all cells – ours and the bacteria – happen all the time. If a mutation occurs that prevents a bacterium from being killed by an antibiotic, this bacterium will live while the others around it are killed when the antibiotic treatment is given.

The resistant bacterium will then reproduce.

Superbugs have evolved in hospitals where there are lots of antibiotics.

The resistant bacteria multiply and share their new genes with other bacteria, which can lead to a set of anti-biotic resistance genes
in a single bacterial cell, and a superbug is born.

Many superbugs live harmlessly on or in the body and only cause problems when the immune system becomes weakened by other illness,
or if they enter a wound.

MRSA

Those who are already ill are most susceptible as their immune systems are already busy fighting something else. This also applies to people who have been weakened by surgery, childbirth, old age or drug treatments, for example.

The young are also at risk, especially babies.

In the same way as any other bacteria – through touching contaminated surfaces and then touching a vulnerable person.

The bacteria may lurk on a surface, someone’s hand or be moving from a part of the body where they do no harm to another part where they can cause an infection.

You can catch superbugs anywhere, but you’re more likely to find them in a hospital as this is where a high concentration of those susceptible to infection are found.

Alongside wounds, superbugs can enter the body via a device such as a catheter or intravenous line. Others enter through the mouth, nose or urinary tract directly.

Superbugs are no easier to catch than other germs, so if you practise good hygiene, you can avoid them.

Wash hands well after going to the toilet, before touching wounds or a sick person, before eating and so on.

There are kits available to protect patients from superbugs, usually containing antibacterial surface wipes, body washes and sprays for fabric.

There is no harm buying one if you or a relative is going into hospital. But there is soap and alcohol hand gel at the hospital already.

If healthcare workers don’t wash their hands when you ask, having a kit nearby would enable a patient to do something if they were worried, and reducing stress is a good way to speed recovery from illness.

Methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile (C.diff) are the most frequently reported. Staphylococcus aureus (S.aureus) is a common skin bacterium, which has become resistant to methicillin, a type of penicillin that used to be able to kill it, as well as other antibiotics.

One in three people have S.aureus living harmlessly on their skin and in their nose, and a proportion carry MRSA harmlessly. It is only when bacteria get into a wound that they cause problems. Infection causes abscesses and boils and can be fatal if it enters the bloodstream.

NHS patients going into hospital for a relevant planned procedure should now be screened for MRSA in advance. If not, you could ask to be, or insist everyone washes their hands before touching you as the MRSA may come from someone else rather than yourself.

If a patient is found to be carrying MRSA, treatment involves using an antibacterial wash or powder and a special cream in their nose. MRSA infections have also been identified in healthy individuals who haven’t been hospitalised, which is called Community- acquired MRSA.

Methicillinsensitive Staphylococcus aureus (MSSA) is the same bacterium and produces the same symptoms as MRSA but it is not resistant to methicillin.

Perhaps the most alarming superbugs around at the moment are S. aureus strains, which produce a toxin called Panton-Valentine Leukocidin (PVL). PVL kills white blood cells and skin tissue. Infections have increased ten-fold in the past six years.

As well as being hard to kill, it is able to infect healthy people. Some strains can’t be killed by methicillin.

In 2010, there were 2,227 cases of PVL in England, up from 224 in 2005.

New Delhi metallo-beta-lactamose (NDM-1) is also a concern. NDM-1 is a gene that can jump between bacteria, making the strain resistant to some of the most powerful antibiotics that are often used as a last resort – hence the moniker hyperbug.

Two types of bacteria have been host to NDM-1: the gut bacterium E.coli and lunginfecting Klebsiella pneumonia. It was brought to the UK by patients who had travelled to countries such as India or Pakistan for medical treatment.

There are only two antibiotics left that can kill these bacteria.

According to the Health Protection Agency, 109 cases of bacteria with NDM-1 have been recorded in the UK to date.

Once resistant strains evolve, the number of infections will remain similar (or fall, hopefully, due to improved hygiene).

However, deaths will increase. Since 2005, there have been only two new antibiotics that have been put through trials.

It is essential that procedures and money are put in place to look for and test novel anti-biotics or other forms of drug treatment that will kill bacteria.

In the meantime, the public (and doctors) must learn not to use antibiotics unless they are absolutely necessary.

Unless drastic steps are taken now, a post-antibiotic era is a matter of when, not if.