Sunday, 17 March 2013

Fighting bacteria
The media in the UK at least has recently been full of concern verging on hysteria about the possibility of bacteria gaining resistance to all known antibiotics. The mechanisms by which germs infect the body and overcome antibiotics is phenomenally complex and anything but random. Often one hears about how bacteria mutate into new forms, almost as though they just randomly and magically transformed themselves from one microscopic bullet into another, so that eventually a form would emerge which could beat the antibodies which protect against them.

One look at even an instructional website for laymen like me shows the daunting complexity of the biomolecular processes at work in what looks like a fight of good against evil in a science fiction movie. See, e.g. see a previous post on the engineering miracle of a bacterium.  In particular it needs to be born in mind that when healthy or hostile bacteria (germs) mutate they do not do so at random but in a way which is structured in both time and space. The mutation process responds to the situation, such as a threat, and occurs only in selected parts of the genome – i.e. parts of the bacterial genome which are involved in essential functions like reproduction do not mutate.  See, e.g., this research from the Francis Crick Institute in Cambridge.

The germs also only attack when they reach a critical number. They know when this number is reached by communicating via signalling molecules called autoinducers, and this process is known as quorum sensing. If potentially harmful bacteria get wrong data they don’t attack at the right time.  So if the signalling between germs could be confused or disrupted this would render them harmless and this strategy is being explored.

Knowing little about biology I am nevertheless puzzled by the apparent absence of antibiotic research based on the recent discovery of bacteria totally isolated for millions of years in an underground cave. It suggests the possibility that there are bacteria in nature already resistant to all antibiotics we are likely to develop in future.

 In a way this does not seems surprising. The medicines used against harmful bacteria are all from a natural world that has been around for many millions of years. Could it be that the research on combating germs should widen its scope to consider not just systematic mutations by bacteria but the possibility that resistant strains might well be propagating around the world through winds, ocean currents, animal movements and human travel, and that whenever a new antibiotic is launched into the environment it will eventually encounter such a germ, and this germ would then be at an advantage over those still being killed by the antibiotic.  

Recently I learned that it is very likely that bacteria permeate not only the biosphere but the Earth's crust, down to several miles. Could this be another means by which bacteria spread around the planet? There is also evidence of soil bacteria being resistant to penicillin. Some scientists suspect that bacteria are embedded in extra-terrestrial debris, such as comets and meteors, along with viruses, but this does not seem to have become mainstream science since the idea was pioneered by Fred Hoyle et al in the 1970s.
Whatever direction is taken by antibiotic research it is now recognised that the way it is funded, developed for use and dispensed to the public needs to be radically revised. There are several promising antibiotics that are now at a dead end because no pharmaceutical company is prepared to take on the huge expense and risk of testing them and getting them though the regulatory hurdles erected by governments in response to demands from the general population and the medical profession, amplified by the media, for ever higher safety standards. Perhaps the research could be done by universities and non-profit philanthropic organisations, with the government issuing prizes to the groups which come up with the best solutions. The bringing to market of the medicines could be done separately on a contract basis with funding by governments and international charities.

Returning to the actual front line battle against germs one solution that has been gaining ground slowly over the decades is the use of bacteriophages. These are viruses which eat germs and were pioneered in the USSR before the Soviet break-up. Success has been achieved in curing certain minor infections but this approach could conceivably lead to big breakthroughs.

Hopefully, the dark memory of a world before penicillin and other antibiotics will be enough to shock us into doing what it takes to get new drugs into use and more prudent ways of dispensing them.

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