Monday, June 29, 2015

No need to finish antibiotic pills

When asked for practical consequences of biological evolution, mainstream educators nearly always point to advice to take all your pills to avoid evolving bacterial resistance. For example, PBS TV:
Evolution of Antibiotic Resistance

This silent animation created for Evolution: "The Evolutionary Arms Race" follows the progression of antibiotic resistance. When a sick person takes antibiotics, the drugs begin to kill off the bacteria. But if treatment stops prematurely, it leaves some microbes alive -- the ones with mutations that make them resistant to the drugs. As these survivors multiply, they pass along their protective mutations to all their descendants. In this way, the bacteria evolves into a new drug-resistant strain. ...

It means taking all the pills that are prescribed, even if you're feeling better.
And U. California Berkeley:
Applying our knowledge of evolution
Evolutionary theory predicted that bacterial resistance would happen. Given time, heredity, and variation, any living organisms (including bacteria) will evolve when a selective pressure (like an antibiotic) is introduced. But evolutionary theory also gives doctors and patients some specific strategies for delaying even more widespread evolution of antibiotic resistance. These strategies include: ...

3. When treating a bacterial infection with antibiotics, take all your pills.
But there are medical experts who say precisely the opposite, such as Discover Magazine:
Conventional wisdom: Antibiotic regimens should be taken in full, even after the patient feels healthy again.

Contrarian view: Shorter courses are often just as effective and do a better job at preventing antibiotic resistance. ...

“The science is clear,” says infectious disease specialist Brad Spellberg of the Los Angeles Biomedical Research Institute. “Every study that has been done comparing longer versus shorter antibiotic therapy has found shorter therapy just as effective.” A few days of taking antibiotics, it seems, should usually be enough to knock infections on their heels, allowing the patient’s immune system to come in and mop up.

Taking the full course of antibiotics unnecessarily wastes medicine, and more drugs translates to increased evolutionary pressure on the harmless bacteria in our bodies. These “good” bugs can develop drug-resistant genes, which can then transfer to bad bugs.
And the London Guardian reports:
You have been taking antibiotics for a sore throat, but after two days you feel better – except that the tablets make you feel sick. So must you keep taking them? Traditional wisdom is that failing to finish the course allows some bacteria to survive. These will be the hardier ones that can resist the same antibiotic should they meet it again. So for your own good, and that of antibiotic resistance worldwide, you should keep taking the tablets.

But last week, in an article in the Medical Journal of Australia, Professor Gwendolyn Gilbert of the University of Sydney wrote: “There is a common misconception that resistance will emerge if a prescribed antibiotic course is not completed.” She argued that there was minimal risk in stopping antibiotics if the signs and symptoms of a mild infection had resolved.

Professor Chris Del Mar, professor of public health at Bond University in Queensland, agreed, saying that, for most acute chest and urine infections, GPs should tell patients to stop taking the tablets once they feel better. Only for some conditions,
Millions of people also use anti-bacterial soap, but I never heard of anyone getting sick from bacteria that evolved to be resistant to the soap. It is true that some bacteria are resistant to some drugs, but those bacteria have also been found in nature where they never would have been exposed to the drugs.

Speaking of evolution-related myths, a recent poll reported:
YouGov's latest research shows that 41% of Americans think that dinosaurs and humans either 'definitely' (14%) or 'probably' (27%) once lived on the planet at the same time. 43% think that this is either 'definitely' (25%) or 'probably' (18%) not true while 16% aren't sure. In reality the earliest ancestors of humans have only been on the planet for 6 million years, while the last dinosaurs died out 65 million years ago.
There are many knowledgeable scientists who adamantly argue that birds are dinosaurs, and that humans and dinosaurs (birds) coexist today.

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