Tuesday 21 February 2012

Infectious diseases


Experts fear the approach of 'impossible to treat' diseases
Alarming rise in bacteria resistant to antibiotics, Government report finds

20 February, 2012

Britain is facing a "massive" rise in antibiotic-resistant blood poisoning caused by the bacterium E.coli – bringing closer the spectre of diseases that are impossible to treat.

Experts say the growth of antibiotic resistance now poses as great a threat to global health as the emergence of new diseases such as Aids and pandemic flu.

Professor Peter Hawkey, a clinical microbiologist and chair of the Government's antibiotic-resistance working group, said that antibiotic resistance had become medicine's equivalent of climate change.

The "slow but insidious growth" of resistant organisms was threatening to turn common infections into untreatable diseases, he said. Already, an estimated 25,000 people die each year in the European Union from antibiotic-resistant bacterial infections.

"It is a worldwide issue – there are no boundaries," he said. "We have very good policies on the use of antibiotics in man and in animals in the UK. But we are not alone. We have to think globally." Between 2005 and 2009 the incidence of E.coli "bacteraemias" [the presence of bacteria in the blood] rose by 30 per cent, from 18,000 to over 25,000 cases. Those resistant to antibiotics have risen from 1 per cent at the beginning of the century to 10 per cent.

"Only one in 20 of infections with [resistant] E.coli is a bacteraemia, so the above data are only the tip of an iceberg of infected individuals," says a report produced by Professor Hawkey's group, commissioned by the Department of Health and the Department for Environment, Food and Rural Affairs.

Dame Sally Davies, the Government's chief medical officer, has pledged £500,000 to fund research into the threat. Drug companies have lost interest in developing new antibiotics because it is increasingly difficult to find new agents and it is not commercially viable – antibiotics are taken for a few days, compared with, say, a heart drug which may be taken for life.

"There are only so many antibiotics available and as we lose them it becomes more and more difficult to replace them," Professor Hawkey said.

The rapid rise in E.coli blood poisoning is thought to be linked with the ageing of the population. E.coli is a common cause of urinary-tract infections but may also cause wound infections following surgery or injury. These are regarded as minor conditions, but if they became untreatable they would be life-threatening.

E.coli infections pose a much bigger problem than MRSA because the bacterium is more common. Only one in 10 people is a carrier of MRSA, but E.coli is present in everyone. "Those who get ill [with E.coli] are rare – but because it is so common it is a big problem," Professor Hawkey said.

Using standard antibiotic regimens, there is a one in 10 chance that treatment of an E.coli infection will fail because the bug is resistant. But, as numbers of resistant infections rise, there will be increasing pressure to use more powerful antibiotics, called carbapenems, which are the last line available. And resistance to those is already emerging. "In the last two or three years we have seen [organisms] develop which destroy carbapenems. That is a great worry," Professor Hawkey said. The warnings follow increasing reports from Europe of patients with infections that are almost impossible to treat. In November, the European Centre for Disease Control and Prevention (ECDC) said up to 50 per cent of cases of blood poisoning with the bacterium K.pneumoniae, a common cause of urinary and respiratory conditions, are resistant to carbapenems in some countries.

Across Europe, the percentage of carbapenem-resistant K.pneumoniae has doubled from 7 per cent to 15 per cent, the ECDC said. Marc Sprenger, the director, said: "The situation is critical. We need to declare a war against these bacteria."

Meanwhile, the UK Health Protection Agency warned doctors in October to abandon a drug usually used to treat a common sexually transmitted disease because it was no longer effective. The agency said that gonorrhoea – which caused 17,000 infections in 2009 – should be treated with two drugs instead of one.

Explained: how bugs adapt to beat antibiotics

Bugs are like all other life forms: they must adapt to survive. Unlike human beings, however, for whom evolution is measured in millennia, reproduction is so rapid among bacteria that they can change in months or years.

With the introduction of a new antibiotic, natural selection goes to work. Most bacteria are killed by the new drug but the natural variation that occurs in any species means a few examples may, by chance, have some quirk in their genetic structure that allows them to survive.

These bacteria are then selected out by the antibiotic, which kills the rest. The mutant bacteria grow in numbers until they become the dominant species



For now, bird flu papers won’t be published
20 February, 2012


GENEVA — Two studies showing how scientists mutated the H5N1 bird flu virus into a form that could cause a deadly human pandemic will be published only after experts fully assess the risks, the World Health Organization said Friday.

Speaking after a high-level meeting of flu experts and U.S. security officials in Geneva, a WHO official said a deal had been reached in principle to keep details of the controversial work secret until deeper risk analyses could be carried out.

“There is a preference from a public health perspective for full disclosure of the information in these two studies. However, there are significant public concerns surrounding this research that should first be addressed,” said Keiji Fukuda, WHO’s assistant director-general for health security and environment.

Biosecurity experts fear mutated forms of the virus that research teams in the Netherlands and the United States independently created could escape or fall into the wrong hands and be used to spark a pandemic.

Gregory Hartl, a WHO spokesman, said that “there must be a much fuller discussion of risk and benefits of research in this area and risks of the virus itself.”

WHO said experts at the meeting included lead researchers of the two studies, scientific journals interested in publishing the research, funders of the research, countries that provided the viruses, bioethicists and directors from several WHO-linked laboratories specialising in influenza.

The H5N1 virus, first detected in Hong Kong in 1997, is entrenched among poultry in many countries, mainly in Asia, but is hard for humans to catch. But it is known to have infected nearly 600 people worldwide since 2003, killing half of them.

Last year, two teams of scientists — one led by Ron Fouchier at Erasmus Medical Center in Rotterdam and another led by Yoshihiro Kawaoka at the University of Wisconsin — said they had found that just a handful of mutations would allow H5N1 to spread like ordinary flu between mammals, while remaining as deadly as it is now.

Such research is seen as vital for scientists working to develop vaccines, diagnostic tests and drugs that could be deployed in the event of an H5N1 pandemic.

In December, the National Science Advisory Board for Biosecurity asked two leading scientific journals, Nature and Science, to withhold details of the research for fear it could be used by bioterrorists.

The board said a potentially deadlier form of bird flu poses one of the gravest known threats to humans and justified the unprecedented call to censor the research.

WHO voiced concerns, and flu researchers from around the world declared a 60-day moratorium on Jan. 20 on “any research involving highly pathogenic avian influenza H5N1 viruses” that produce easily contagious forms.

Bruce Alberts, editor-in-chief of the journal Science, said it is likely the paper submitted to Science and to the journal Nature will be published in full. When asked how the journal is safeguarding copies of the as-yet-unpublished paper, he said it is in a locked electronic file and is password-protected. Reviewers of the paper were asked to destroy their copies.
Alberts said it is still not clear how the scientists in Geneva plan to handle biosafety issues mentioned by the group, and it is still not clear when the papers will be published, but it will likely not be years.

“I hope this does not cause the world governments and WHO to stop working on this problem,” Alberts said of any potential fallout from the decision at a news briefing at the American Association for the Advancement of Science meeting in Vancouver.

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