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Showing posts with label antibiotics. Show all posts
Showing posts with label antibiotics. Show all posts

Tuesday, 12 March 2013

Superbug threat is 'ticking time bomb'

reposted from: http://www.nhs.uk/news/2013/03March/Pages/Superbug-threat-is-ticking-time-bomb.aspx
crabsallover highlights, key points, comments / links.


There are claims across the media that antibiotic resistance is a ‘ticking time bomb’, with the Daily Express claiming “Superbug threat 'ranks alongside terrorism'”.
These headlines reflect the views of England’s Chief Medical Officer, and arguably could be viewed as understated.
The Chief Medical Officer, Professor Dame Sally Davies, warned of the growing threat from antibiotic resistance ahead of the publication of an in-depth report on the issue (PDF, 3.5MB). In her report, Professor Davies says antimicrobial resistance represents a threat that may be ‘as important as climate change for the world’.
Antimicrobials (drugs used to treat infections from bacteria, viruses and fungi) include antibiotics, which are an essential component of modern medicine and used to treat bacterial infections.
Increasingly widespread use of antimicrobials, and antibiotics in particular, is leading to the organisms causing these infections adapting and surviving. As this resistance develops, it can render treatment of infections less effective and eventually the infections may become untreatable.
Antibiotic-resistant infections, such as MRSA and multi-drug resistant tuberculosis have been increasing over the last two decades; yet few new antibiotics have been developed. While the spread of antimicrobial resistance can be slowed (for example, by good hygiene), new antibiotics are needed to more fully address the problem.

Antibiotic resistance – new threats

The main causes of resistant bacterial infections such as MRSA andClostridium difficile have fallen sharply in the UK due to simple but effective hospital hygiene measures.
Yet the Chief Medical Officer’s report highlights other causes for concern, such as:
  • multi-drug resistant tuberculosis – estimated to kill 150,000 each year globally
  • E. coli – which now accounts for one in three cases of bacterial infections in the blood in the UK
  • NDM-1 – a bacteria detected in India, of which some strains are resistant to all types of antibiotics

What is antibiotic resistance and how does it develop?

Antibiotics are often used to treat bacterial infections, and are a cornerstone of infectious disease care. They have transformed medical care since they became widely available after World War Two – resulting in a sharp drop in deaths from infectious disease.
However, bacteria evolve in response to their environment. Over time, they can develop mechanisms to survive a course of antibiotic treatment.
This ‘resistance’ to treatment starts as a random mutation in the bacteria’s genetic code, or the transfer of small pieces of DNA between bacteria. If the mutations are favourable to them, they are more likely to survive treatment, more likely to be able to replicate and therefore more likely pass on their resistant nature to future generations of bacteria. When taken correctly, antibiotics will kill most non-resistant bacteria, so these resistant strains can become the dominant strain of a bacteria. This means when people become infected, existing treatments may be unable to stop the infections.
We cannot stop the random DNA mutations that are one way antibiotic resistant strains of bacteria emerge. However, we can exert some control over the speed and spread of antibiotic resistance by several methods, such as:
  • Breadth of use: the more antibiotics are used, the more quickly resistance generally develops, this makes reducing unnecessary use important (both in healthcare and other fields such as veterinary medicine).
  • Incorrect use: resistance is more likely to spread if you do not finish a course of antibiotic treatment (as the drugs won’t have a chance to kill off all the bacteria), or if broad-spectrum antibiotics, which often serve as ‘last-line’ treatments, are used where a more narrow and targeted option is available and appropriate.
  • Infection control: containing and preventing infectious diseases – such as through diligent cleaning and hand washing – can reduce the need for antibiotic use.

How much of a danger is antibiotic resistance?

Antibiotic resistance can render previously treatable infections untreatable. For instance, tuberculosis (TB) cases have been increasing steadily in the UK for the past 20 years, with an increasing number of cases being resistant to the first-choice antibiotics traditionally used to treat the infection.
Widespread antibiotic resistance could have a far reaching healthcare impact. For example, emerging antibiotic resistance increases the chance that surgical sites could be infected by bacteria resistant to antibiotics and cause infection in people who may already be vulnerable as a result of their underlying illness or from having major surgery.
The Chief Medical Officer says that other treatments which lower our immune response – including immunosuppressants (for example, to prevent the body rejecting transplanted organs) or chemotherapy for cancer – would also not be viable in the face of widespread antibiotic resistance. 
Professor Davies, has said that “antimicrobial resistance poses a catastrophic threat. If we don’t act now, any one of us could go into hospital in 20 years for minor surgery and die because of an ordinary infection that can’t be treated by antibiotics. And routine operations like hip replacements or organ transplants could be deadly because of the risk of infection”.

Why have no new antibiotics been developed?

Critics of the pharmaceutical industry would argue that the reason is simple – there is no profit in it.

This has been disputed by the pharmaceutical industry. An industry spokesperson quoted in The Guardian pointed out that there are ‘pharmaceutical companies actively involved in
researching and developing new antimicrobial medicines’.

The Chief Medical Officer argues that the best way forward would be a public-private partnership, where governments help support and fund the work of drug companies in order to create new antibiotics.

What has the Chief Medical Officer called for?

The Chief Medical Officer wants action to tackle antibiotic/antimicrobial resistance in several areas. She wants to change the medical practices that increase the risk of developing or exacerbating resistance, to improve government monitoring of (and response to) emerging resistance, and to create incentives for new antibiotics to be developed.
In healthcare in particular, the Chief Medical Officer recommends:
  • antimicrobial resistance to be added to the national risk register (a series of contingency plans designed to co-ordinate government response to civil emergencies), and to be taken seriously by politicians worldwide
  • improving the monitoring and surveillance of resistance, both within the NHS and worldwide
  • co-ordination of efforts between the healthcare and pharmaceutical industries to prevent resistance to current antibiotics from developing and spreading, and to encourage the discovery and development of new antibiotics
  • improving hygiene measures to prevent the spread of healthcare-associated infections
The Chief Medical Officer also wants action on antimicrobial resistance beyond hospitals and other areas of healthcare, including:
  • better home and community based infection control measures
  • a focus on antibiotic resistance in animals, managed by the Department for Food, Environmental and Rural Affairs
  • co-operation between Public Health England and the NHS to improve the detection and treatment of infections acquired abroad
  • better promotion of vaccination programmes, reducing the need for some antibiotic treatments

What is likely to happen next?

The Department of Health is due to publish a UK Antimicrobial Resistance Strategy, outlining how it will take steps to address this issue. This will include plans to:
  • support responsible antibiotic use
  • improve surveillance mechanisms
  • encourage the development of new diagnostic tests, therapies and antibiotics

What can we do to prevent antibiotic resistance?

We can all take steps to help slow the spread of resistant microbes.
Understanding when antibiotics are appropriate can be complicated. We often think of antibiotics being used to treat “a chest infection”, yet most common respiratory infections will go away on their own without any treatment. In addition; most coughs, colds and sore throats are caused by viruses, rather than bacteria, so an antibiotic would be not be an effective treatment for them. If we use antibiotics to treat these relatively minor viral complaints, not only is the treatment ineffective, it increases the chances of antibiotic resistance developing, making other more serious conditions such as TB more difficult to treat.
If your doctor does prescribe antibiotics for you, make sure that you’ve discussed and understood how to take them correctly, and that you take all the prescribed pills, regardless of whether you still have symptoms. This is because if you do not take the full prescribed dose, the chances are that some of the bacteria will not be killed, and that these are more likely to be resistant strains. This could be bad for you, and it could be bad for lots of other people too.
Read more about what you can do to tackle the problem of antibiotic resistance.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links to the headlines

Warning issued over superbug threat. Channel 4 News, March 11 2013

Further reading

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Monday, 24 December 2012

'Little point taking antibiotics for coughs'

reposted from: http://www.nhs.uk/news/2012/12December/Pages/Antibiotics-harmful-and-ineffective-for-coughs.aspx
crabsallover highlights, key points, comments / links.


Wed Dec 19, 2012 11:40 
‘The winter may be peak season for coughs and colds but there is no point in taking antibiotics to shift them’, The Independent reports. Its story comes from a large trial looking at whether a commonly used antibiotic, amoxicillin (wikipedia), can relieve symptoms of acute lower respiratory tract infections such as coughs and bronchitis.
The study found that antibiotics didn’t shorten the time people had symptoms for, nor did they reduce the severity of respiratory symptoms. This is unsurprising as the majority of coughs and cases of bronchitis are thought to be caused by viral, not bacterial, infection – and antibiotics are useless against viral infections.
If anything, as the Daily Mail points out, antibiotics may be doing more harm than good in these types of infection, as they carry a small risk of side effects such as nausea and rash.
This large, well-designed trial provides firm evidence that taking antibiotics for self-limiting conditions, such as the cough or bronchitis, has little benefit, even for older people.

Where did the story come from?

The study was carried out by researchers from a number of institutions in Europe including the University of Southampton and Cardiff University in the UK. It was funded by the European Commission, UK National Institute for Health Research, Barcelona Ciber de Enfermadades Respiratorias, and Research Foundation Flanders.
The study was published in the peer-reviewed medical journal The Lancet Infectious Diseases.
The media reported the story accurately, though The Independent’s use of the term “coughs and colds” was a little misleading. The study looked at the use of antibiotics for all lower respiratory tract infections (LRTIs), commonly known as chest infections. A cold usually only affects the upper respiratory tract (nose and throat), although some viruses can affect both the upper and lower airways.

What kind of research was this?

This was an international randomised placebo controlled trial (RCT) that aimed to look at both the benefits and harms of giving people amoxicillin for lower respiratory tract infections (LRTIs), one of the most common acute (short-term) illnesses seen by GPs.
LRTIs are those that affect the windpipe and the lungs (upper infections affect the nose and throat). Symptoms may include cough, fever, fatigue and general sense of feeling unwell. LRTIs may be caused by viruses (such as those known to be associated with the cold, including rhinoviruses) or bacteria.
The researchers point out that most patients with LRTIs receive antibiotics, partly because they worry about the symptoms and also because some doctors may give antibiotics as a precaution to try to prevent complications, such as pneumonia (a more severe type of lung infection), even if there is uncertainty of a bacterial infection being present.The researchers argue that prescribing antibiotics in this way is costly and is one of the main causes of antibiotic resistance.
In 2009, a systematic review of the use of antibiotics for acute bronchitis showed moderate benefits and no significant short-term harm, so the debate about their use for LRTIs has continued, with little data from placebo controlled trials, say the researchers.
Most doctors tend to prescribe antibiotics for older patients who also have other illnesses (as they are more vulnerable to the harmful effects of infection), but their role for healthier older people with coughs is unclear.

What did the research involve?

Between 2007 and 2010, researchers recruited patients attached to primary care practices in 12 countries; Belgium, England, France, Germany, Italy, the Netherlands, Poland, Slovakia, Slovenia, Spain, Sweden, and Wales.
Eligible patients were aged 18 or over and had seen their doctor for the first time with either an acute cough (one which had lasted 28 days or less) or an illness in which cough was the main symptom but which the doctor thought due to an LRTI.
Patients who had been diagnosed with pneumonia were excluded, as were patients whose cough was found to be caused by conditions other than infection (such as a clot on the lung or allergy), or who had been prescribed antibiotics in the previous month. Patients were also excluded if they couldn’t provide informed consent, were pregnant, allergic to penicillin, or had immune system deficiencies.
Using computer-generated random numbers, the researchers randomly assigned participants to one of two groups. The first group were given amoxicillin (dosage 1g three times a day for seven days) and the second a placebo drug (dummy treatment), identical to amoxicillin in appearance, taste and texture, for the same period. Neither patients nor the doctors involved knew which participants were allocated to which group (double-blinded).
The researchers wanted to see whether taking antibiotics affected the duration of symptoms that were described as “moderately bad” or worse (see description of symptom scale below). They also looked at whether antibiotics had any effect on the severity of symptoms in days two to four, or on the development of new or worsening symptoms, such as:
  • a return visit to the doctor with worsening symptoms
  • new symptoms or signs
  • illness requiring hospital admission
The patients’ doctors recorded the severity of symptoms at baseline and rated them as:
  • no problem
  • mild problem
  • moderate problem
  • severe problem
The patients were asked to complete a daily symptom diary for the duration of the illness, recording the severity of cough, phlegm, shortness of breath, wheeze, blocked or runny nose, chest pain, muscle aches, headaches, disturbed sleep, general feeling of being unwell, fever and interference with normal activities. Symptoms were scored on a scale of 0 to 6, with 0 being “no problem” and 6 “as bad as it could be”.
Patients also recorded non-respiratory symptoms such as diarrhoea, skin rash and vomiting. The symptom diary used in the research is considered reliable.
Researchers telephoned participants after three days to offer support and answer any questions about completion of the diary. If the diary was not returned after four weeks, they collected information about symptom duration and severity with either a short questionnaire or a telephone call.
The patients’ doctors registered all contacts with patients for four weeks after the initial consultation including referral to hospital and out-of-hours contacts.
Using patients’ diaries, the researchers analysed the results using standard statistical methods. They also completed a separate analysis of patients aged 60 or over and for patients aged 70 or older.

What were the basic results?

The study had 3,108 patients agree to take part, though 1,047 were ineligible, mostly because they refused to be randomly assigned to an antibiotic or placebo. After exclusions, 2,061 patients were randomly assigned to one of the two groups:
  • 1,038 to the amoxicillin group
  • 1,023 to the placebo group
The researchers found:
  • There was no significant difference between the amoxicillin and placebo groups in how long “moderately bad” or worse symptoms lasted (hazard ratio 1.06, 95% confidence interval [CI] 0.96 to 1.18).
  • There was no significant difference between the two groups in the average severity of symptoms (1.69 with placebo versus 1.62 with amoxicillin, difference –0.07 [95% CI 0.15 to 0.007]).
  • New or worsening symptoms were significantly less common in the amoxicillin group than in the placebo group (162 [15.9%] of 1,021 patients versus 194 [19.3%] of 1,006, p=0.043, number needed to treat 30).
  • Cases of nausea, rash, or diarrhoea were significantly more common in the amoxicillin group than in the placebo group (28.7% versus 24%, number needed to harm 21, 95% CI 11 to 174), and one case of anaphylaxis (severe allergic reaction) was noted with amoxicillin.
  • Two patients in the placebo group and one in the amoxicillin group needed to be admitted to hospital.
  • No-one died.
  • There was no evidence of any benefit for amoxicillin in patients aged 60 years or older (n=595) or in those aged 70 or over (n=266).

How did the researchers interpret the results?

If pneumonia and other complications are not suspected, amoxicillin has little benefit for acute lower respiratory tract infections overall or for patients aged 60 or over, and has a slight risk of side effects, they say.
Any mild short-term benefits of antibiotic treatment should be balanced against the risk of side effects and in the long term of fostering antibiotic resistance.

Conclusion

This large international trial provides convincing evidence that for most patients with an uncomplicated, acute cough where pneumonia is not suspected, antibiotics do not shorten how long symptoms last or their severity.
Antibiotics did reduce the risk of new or worsening symptoms. However, as the researchers point out, 30 people needed to be treated with amoxicillin to prevent just one case of new or worsening symptoms. This is called the ‘number needed to treat’ and is a useful way for researchers to compare the effectiveness of treatments.
This ‘number needed to treat’ of 30 has to be balanced against the increased rate of side effects. In this study, the ‘number needed to harm’ was 21. The fact that the number need to harm is lower than the number needed to treat means that more people would get side effects from the treatment than might be helped by it. However, the severity and duration of these side effects has to be weighed up against the symptoms that are being eased.
Even if there was a more favourable trade-off between number needed to treat and the number needed to harm, doctors, health policymakers, and even us ordinary punters, have to consider the wider (and growing) problem of antibiotic resistance. Every time we use an antibiotic to treat a trivial, self-limiting condition, such as a bacterial chest infection, we increase the risk of that antibiotic subsequently failing to treat a life-threatening condition such as bacterial meningitis. However, as the authors point out, the results may not apply to older people with other serious illnesses or weakened immune systems, where antibiotic treatment could be warranted.
There are a few limitations in this study that are worth noting, including :
  • About a third of patients recruited chose not to be randomly assigned, so did not take part in the study. This could lead to “recruitment bias”, although the researchers say there is no evidence of this.
  • Only one type of antibiotic was used in the trial. It is possible that other types might be more effective, although this is unlikely and some others may also have more side-effects.
  • The small number of patients aged 70 or over (266) may mean the study did not have the power to detect any benefit for antibiotics in this group.
  • Poor adherence may have affected the results, although more than 90% of patients in both groups reported taking the study drugs by day five.
In conclusion, this study shows that for most patients with uncomplicated lower respiratory tract infections, antibiotics offer little relief from symptoms. As the researchers point out, there is a major challenge for doctors and researchers in finding ways to identify the few patients with bacterial infections who would benefit from antibiotics.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Links To The Headlines

Antibiotics 'ineffective for coughs'. BBC News, December 19 2012

Links To Science

Little P, Stuart B, Moore M, et al. Amoxicillin for acute lower-respiratory-tract infection in primary care when pneumonia is not suspected: a 12-country, randomised, placebo-controlled trial. The Lancet Infectious Diseases. Published online December 19 2012
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