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A future for antibiotics?

A brief history of antibiotics

 

Antibiotics have transformed medicine, but the bugs are catching up.

Antibiotics have revolutionised medical care in the 20th century, but in recent years bugs have been winning the battle against the medical profession.

Penicillin was the first antibiotic, discovered by Alexander Fleming in 1929, but it was not until the early 1940s that its true potential was acknowledged and large scale fermentation processes were developed for the production of antibiotics.

They have been used to treat a wide variety of often dangerous illnesses caused by bacteria.

In the early years, new antibiotics were developed faster than bacteria developed resistance to them. But the bugs have fast caught up. In the 1950s and 60s, many new classes of antibiotics were discovered.

But in the 1980s and 1990s, scientists have only managed to make improvements within classes.

The Standing Medical Advisory Committee's report, The Path of Least Resistance, published this week, says: "In the closing years of the century, there is an uneasy sense that micro-organisms are 'getting ahead' and that therapeutic options are narrowing."

Breeding

Some low-grade hospital bugs are now resistant to all antibiotics and several more dangerous ones can only be effectively treated by one or two antibiotics or antibacterial agents.

And hospitals are not the only breeding ground for these superbugs. Community homes and other places which are home to vulnerable groups of people have noted a marked rise in drug-resistant bugs. Worldwide, a new drug-resistant strain of tuberculosis is causing concern, particularly as the disease is enjoying a resurgence.

Even if resistance to some antibiotics does not prevent treatment because others are available, it still costs money. Patients may have to try several treatments to see which works and they may have to stay in hospital longer as a result.

Moreover, alternative drugs may be more expensive and have greater side effects.

A future for antibiotics?

Just as viruses attack humans, so they can kill bacteria

Scientists are working hard to find new ways to defeat bacteria that are increasingly resisting the antibiotics already available.

These range from continuing to develop new antibiotics to keep up with bacteria's rapid evolution to giving bacteria themselves disease - bugs are, like larger organisms, susceptible to viruses.

Since the introduction of penicillin bacteria have been proving themselves ever more adept at defeating antibiotics - soon after its introduction in the 1940s resistant strains of bacteria began to appear. The response has always been to develop new classes of antibiotics that can tackle the resistant strains, and until recently doctors were well ahead of the game. But with the emergence of bacteria resistant to even the most powerful antibiotics, scientists are having to look at other approaches.

Adapting to change

Researchers at the University of Limerick are taking another approach, and working against the very characteristics that make a bacterium resistant.



Resistance occurs partly because bacteria reproduce so quickly - one bacterium with a mutation can survive the antibiotic and reproduce millions more with the same resistance within the space of a day.

The Limerick scientists think they have found a way to adapt the antibiotic so that it recognises the mutant bacteria and destroys them before they reproduce. They say some bacteria are able to negate penicillin's infection-fighting properties by producing enzymes that cut out a critical part of the penicillin molecule.

The team has produced a prototype penicillin structure that works by incorporating a unique fragment to the penicillin molecule, which is fatal to bacteria and specifically activated only when a bacterium attempts to change the drug's molecular structure.

Diseased bugs

But the ultimate answer may lie outside antibiotics with an idea that first appeared before the First World War but was abandoned after the recognition of penicillin's power in 1943.

It involves exploiting bacteria's natural enemy - viruses known as bacteriophages, which enter the bacterium and kill them. They have proven more effective than antibiotics in some animal studies.

Work in the former Soviet Republic of Georgia and the UK is looking at how to exploit them in treating infected humans. However, bacteriophages are extremely specific and have to be matched to exact strains of bacteria, meaning that an infection that kills rapidly could not be treated quickly enough. The ultimate superdrug - that can kill all known germs without killing their human host - is still a long way off, and, given the remarkable power of bacteria to evolve, its supremacy would most likely be short lived.


Date: 2015-12-11; view: 930


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