Tuesday, November 10, 2009

Beware of Superbug ,Do not overuse Antibiotics

When bacteria are exposed to antibiotics, the susceptible bacteria die and only the rare bacteria already resistant to the antibiotics live. The problem is those surviving bacteria then multiply, spreading their antibiotic resistance.


What we need are new antibiotics to treat these infections. Unfortunately, at the same time as the bacteria are getting more resistant, fewer antibiotics are being developed. The microbes have leapt ahead - and medicine is not even trying to keep pace. How can that be?

Microbe is an organism that is microscopic (usually too small to be seen by the naked human eye),they include bacteria, fungi, archaea, and protists; microscopic plants (called green algae); and animals such as plankton and the planarian. Some microbiologists also include viruses, but others consider these as non-living.[1][2] Most microorganisms are unicellular (single-celled), but this is not universal, since some multicellular organisms are microscopic, while some unicellular protists and bacteria, like Thiomargarita namibiensis, are macroscopic and visible to the naked eye.[3]

it comes to the rise in drug-resistant bacteria, people often blame doctors' misuse of antibiotics...click read on to read more...

They think to themselves: 'Physician overuse of antibiotics causes antibiotic resistance among microbes. Therefore, if we could only convince physicians to use antibiotics responsibly, then we could stop antibiotic resistance and win the war against microbes.'

Doctors prescribing antibiotics are not to blame for the rise in superbugs

Unfortunately, this is wrong. Microbes are programmed to become resistant.

It may surprise people to learn that there are five to ten times more microbes living on and in every human than there are human cells in our bodies - between 50 and 100 trillion microbes versus about 10 trillion human cells.

Humans pale in comparison to the adaptability of microbes, which inhabit literally every possible clime and environment on the planet, including deep in the earth's crust.

This degree of adaptability is due to two fundamental features. First, bacteria can reproduce almost impossibly quickly.

Many replicate in just 20 to 30 minutes (it takes humans 20 to 30 years). At this rate, a single E. coli bacterium can create 69 billion progeny in 12 hours.

Now, that's an enemy for you. But microbes also have a virtually limitless ability to diversify.


Of those 69 billion offspring, 230 million of them may contain unique mutations that cause them to differ slightly from their ancestral strain, and 1.5 million may contain mutations that specifically enhance their ability to survive despite hostile environmental conditions, such as the presence of antibiotics.

When bacteria are exposed to antibiotics, the susceptible bacteria die and only the rare bacteria already resistant to the antibiotics live. The problem is those surviving bacteria then multiply, spreading their antibiotic resistance.

Microbes do not need our help in creating antibiotic resistance. They are doing just fine on their own.

What human beings can do is affect the rate of spread of preexisting bacterial resistance.

Using antibiotics correctly will not stop microbial resistance: it only slows it down so that we can find a real solution to the problem.

But who's looking for that solution? For years, it's been clear to those working in infectious diseases that antibiotics were no longer being developed by many pharmaceutical companies.

A study I worked on in 2004 found only five new antibacterial drugs in development.

This compared with eight to treat bladder hyperactivity and seven for either acid reflux or irritable bowel syndrome, and four for erectile dysfunction.
Maybe it's just me, but it seems like not having antibiotics to treat life-threatening infections is more serious a problem than an insufficient number of erections.

In fact, there's been something like a 75 per cent decline in antibiotic development since 1983. This situation is what we in the field refer to as 'bad'.


This is not the result of declining investment by pharmaceutical companies, though: between 1998 and 2002, the ten largest pharmaceutical companies increased their collective research and development budget by 31 per cent.

So why aren't antibiotics being developed? Basically, the main reason is money.
Discovering an antibiotic compound is only the first step in a drug's development.

The next stage is human clinical trials. A recent analysis found that the average cost of a so-called Phase III drug trial (the definitive study to prove it is effective) is £51 million.

Preliminary safety trials can also cost many millions. So pharmaceutical companies are understandably conservative about selecting which drugs to go ahead with.
But despite these barriers, pharmaceutical companies are still developing drugs. What makes antibiotics different?

Unfortunately, antibiotics have a lower rate of return on investment than other drugs. Antibiotics are short-course therapies that cure their target disease and are typically taken for no more than two weeks.

Chronic diseases, however, are treated with therapies that simply suppress symptoms and are taken for life - for example, cholesterol-lowering drugs or drugs for high blood pressure.

There is no better example of the power of a chronic illness to drive interest in drug development than HIV infection. Over the past 15 years, virtually the same number of new drugs targeting just HIV have come to the market as for the treatment of all bacterial infections combined.
It's not difficult to see it from the drug companies' perspective. HIV drugs are taken for the remainder of a patient's life, and typically started in relatively young patients.

This combination results in big profits.


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