Friday November 16 2012
Antibiotics should not be routinely used to treat infection
Not for the first time the issue of antibiotic resistance is in the news. The Independent reports that “Antibiotics crisis will mean routine infections are fatal,” while The Guardian headlines that “Antibiotics resistance growing at alarming rate.”
Both media resources contain warnings from England’s Chief Medical Officer, Professor Dame Sally Davies, that in the future we could have no cures for infections, which could mean that even minor injuries or routine operations could prove fatal if an infection occurs. In the pre-antibiotic era, infections could often spread into the blood causing multiple organ failure and death.
Professor Davies is quoted in the media as saying: “Antibiotics are losing their effectiveness at a rate that is both alarming and irreversible – similar to global warming... Bacteria are adapting and finding ways to survive the effects of antibiotics, ultimately becoming resistant so they no longer work”. The warnings follow a similar call earlier this year by Margaret Chan, head of the World Health Organization, who warned of the who “global crisis in antibiotics”.
The media reports follow press releases issued by the UK Health Protection Agency (HPA) and European Centres for Disease Control in preparation for European Antibiotic Awareness Day (EAAD) on November 18.
The HPA wants our attitudes to antibiotics to change.
Most common illnesses, such as coughs, colds, sore throats and stomach upsets, will get better by themselves without the need for antibiotics. Antibiotics (and other antimicrobials such as antivirals and antifungals) certainly have an important and often lifesaving role in role in healthcare, but prescribing them unnecessarily contributes to the problem of bacteria developing resistance to the antibiotics that they would have once been susceptible to.
This creates a need for developing stronger antibiotics in the future, but whether this can be achieved is not certain.
Professor David Livermore, an international expert on antibiotic resistance, says: “While disaster isn’t imminent just yet, we do need to take action now to protect ourselves for the future.”
What is antibiotic resistance?
Antibiotic resistance is the term used to describe bacteria no longer being killed by an antibiotic that they would previously have been killed by.
Resistance isn’t a problem only limited to antibiotics: resistance can be to antibiotics used to treat bacterial infection, to antivirals to treat viruses, or to antifungals to treat fungal infection. So the wider term ‘antimicrobial resistance’ is also sometimes used to encompass the whole problem, which is where any particular micro-organism is no longer killed by an antimicrobial medicine to which it had previously been susceptible.
How antimicrobial resistance develops
Antibiotic (or antimicrobial) resistance develops when bacteria (or other organisms) are regularly exposed to the same antimicrobial drug over time. Some organisms will eventually mutate and develop resistance to the action of this drug.
In populations of bacteria exposed to antibiotics, the resistant bacteria survive and replicate in preference to the susceptible bacteria. This means that the favourable ‘resistance trait’ will be passed on to future generations of bacteria. This is a form of evolutionary selection – Darwin’s ‘survival of the fittest’ at work.
Using antibiotics to treat common, mild illnesses unnecessarily speeds up the problem of antibiotic resistance.This is because the bacteria are being more regularly exposed to these antibiotics than they would be if they were reserved only for the cases when they were really needed.
Why you need to take the full course of medicine
Resistance is also caused when antibiotics are not taken for the fully prescribed course. Taking only a partial course of antibiotics means that bacteria will be exposed to the antibiotic but are not given a strong enough course to kill them, resulting in the bacteria surviving and replicating. Consequently, future strains may be more likely to mutate and develop resistance. An HPA survey found that a quarter of people who are prescribed antibiotics don’t finish the prescribed course.
MRSA: an example of why antibiotic stewardship is needed
The highly resistant hospital bug MRSA (methicillin-resistant Staphylococcus aureus) is a high-profile example of bacteria that has developed antibiotic resistance. Staphylococcus aureus bacteria are commonly carried on our skin, but can cause infection when they get into the body (for example, infecting people with open wounds or who have a catheter). When penicillin was first developed in the 1940s, Staphylococcus aureus were sensitive to it. With regular exposure the bacteria eventually developed the ability to resist the actions of penicillin, and therefore stronger antibiotics had to be developed.
Methicillin is a penicillin-like antibiotic that was developed in the 1960s, and to which Staphylococcus aureus were then susceptible to at the time. However, over time, some Staphylococcus aureus bacteria developed resistance to methicillin. Methicillin has since been replaced by flucloxacillin, which remains a strong antibiotic that can be used to treat most Staphylococcus aureus infections. However, flucloxacillin cannot treat MRSA, and further stronger antibiotics have had to be developed that are able to treat MRSA.
Another potential cause of concern is the emergence of strains of tuberculosis that have evolved antibiotic resistance to antibiotics. One particular strain, extensive multi-drug resistance tuberculosis (XDR-TB), has a resistance to four or more antibiotics. XDR-TB can take up to 18 months to treat and can also be fatal, especially if cases occur in developing world countries where access to good-quality healthcare is often limited.
What does the HPA report about antibiotic resistance?
In preparation for European Antibiotic Awareness Day on November 18, Professor David Livermore, an international expert on antibiotic resistance, has summarised the key facts about antibiotic resistance and antibiotics. He says that while antibiotics revolutionised medicine, they carry the seeds of their own destruction in that they necessarily lead to resistant bacteria strains.
Professor Livermore’s main concerns are that some antibiotics have already been lost to resistance, for example penicillin is no longer effective for staphylococcal wound infections. Meanwhile, new antibiotics are hard to find and to license and research effort has slowed. He also says that we need to try to slow the selection and spread of resistance through ‘right drug, right dose, right duration’ but also through prevention, such as promoting the use of condoms to stop the spread of resistant sexually transmitted infections.
Professor Livermore says that while there has been some success, the tide of the war against antimicrobial resistance runs against us. The number of cases of MRSA blood poisoning in English hospitals is said to have been reduced by over 80% since a peak of cases early in 2003/04. This has largely been due to better infection control. However, resistance is increasing among certain bacteria, especially those referred to as ‘gram-negative’ bacteria, which mostly cause infections in hospitalised patients.
Professor Livermore says that rises in resistance like those seen for E. coli force doctors to use much stronger antibiotics (such as carbapenems), which were previously the antibiotics ‘reserved’ for use only when other treatments had failed. Now carbapenems are being used much more and resistance to them is developing as well. Currently there is usually an antibiotic available to treat any bacterial infection, though they are not always ideal and can cause other serious side effects or are just not as good at killing the bacteria.
What does the WHO report about the global problem?
The WHO reported in March this year that every year there are about 440,000 new cases of multidrug-resistant tuberculosis, which is responsible for at least 150,000 deaths. Other major global issues are the resistance to anti-malarial medicines that are used to treat malaria parasites. Hospital-acquired infections due to MRSA are also a global problem.
The WHO says that inadequate focus on new treatments, poor infection practices and weak surveillance systems all contribute to antibiotic (and antimicrobial) resistance globally.
How can I help the problem of antibiotic resistance?
On European Antibiotics Awareness Day (EAAD), the Health Protection Agency (HPA) says everyone should think twice before they ask for antibiotics from their doctor for their cold and flu symptoms.
Dr Cliodna McNulty, the HPA’s head of primary care and lead on European Antibiotic Awareness Day, says: “We are now well into winter and the usual season of people being unwell with lots of nasty viruses so it is a perfect time to remind people that antibiotics don’t help most coughs, colds and flu or sore throats get better faster.
“We all seem to forget just how awful you can feel with a bad cold, let alone flu, and this maybe makes us think that we are more poorly than we really are and that we need antibiotics to get better. But this isn’t the case, and using your favourite over-the-counter medicines that can help to ease headaches, aching muscles and stop your nose running will make you feel a lot better.”
Dr McNulty also warns that if you have had an antibiotic in the last six months your next infection is twice as likely to be resistant to antibiotics.
So the overall message is “if you don’t need them don’t take them”. The HPA advise people to remember that “doctors are now advised not to routinely give antibiotics for chest infections, ear infections in children and sore throats”. They suggest that patients ask their doctor for an information leaflet about antibiotics.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on twitter.