Sunday, June 30, 2013

Bacteria - the world's first inhabitants!



In the late 1960s, US Surgeon General William H. Stewart is alleged to have made the now infamous declaration that “[it] is time to close the book on infectious diseases and declare the war against pestilence won”. Well time has certainly proved that comment to be totally false! Bacteria and other microbial organisms are past masters at adapt and change techniques and leave we human Johnny come latelies eating their dust when it comes to facing such challenges. Here are a few facts that help put the whole “war on pestilence” into some perspective:

Microbes have been around for 3.5 billion years and have adapted to most environments on the planet: which has allowed them to survive freezing, boiling, to living without oxygen or sunlight and in conditions of extreme salinity. They can survive pressure at the bottom of oceans that would crush just about any man made submersible and thrive on the poisonous gas Hydrogen Sulphide.

These Microbes are also ubiquitous and represent 60% of the Bio-mass on earth and that figure rises to 90% if you remove cellulose from the equation, and yet we’re talking about individual organism that can often only be viewed through high powered microscopes. In fact, as noted in a previous program on the Human Micro-Biome, there are about 6 times as many bacteria living on or in we humans than we have human cells.

Then there is the fact that a bacteria has the ability to replicate in as short a time as 20 to 30 minutes as compared with humans who take two to three weeks to replace our skin and about 20 to 30 years to completely replace all our bodily cells! So not only do they out number us by a factor of 10 to the power 22, they’ve existed for a 1000 times longer and can reproduce half a million generations in the time it takes us to live one generation!

The genetics of bacteria are primed to deal with challenges, and the addition of human generated antibiotics in the last 80 years must surely rate as just a tiny hiccough in their ability to populate the globe and all that lives upon it: and therein lies our challenge.

When Albert Florey and Alexander Flemming first introduced the penicillin antibiotic the results were astounding: susceptible bacteria were destroyed and infections previously seen as a death sentence were completely cured, which led to enormous activity in research to find other effective antibiotics to treat a whole spectrum of infectious diseases. And that was perhaps when the folly of man led to over-confidence in the use of such chemicals against seemingly defenseless germs!

Such overconfidence created an environment whereby antibiotics were prescribed freely and in many cases for probably the wrong reasons - especially against viruses where they have absolutely no place to play at all. But of even more concern has been the worldwide use of antibiotics in farming and for treating domestic animals too. In 1999 in the UK alone, 1,225 metric tonnes of antibiotics were used and 63% of that total was used on farm and domestic animals. When you consider how many hundreds of thousands of tonnes of antibiotics are now being used worldwide in our food chain and in our homes, then it is not perhaps surprising that we face a perfect storm of bacterial resistance.

However, it’s not just the overuse of antibiotics that we should be concerned about, there is also the issue that there has not be a new class of antibiotics released onto the market for many many years and according to reports, there are virtually non in the pipeline of the pharmaceutical companies either. There are a number of reasons for this, and one of those is the paradoxical past success of antibiotics.

Most antibiotics are given in 5 to 7 day courses and then the infection is fixed. Such a short course of medications doesn’t offer the Pharmaceutical Industry much incentive to produce new treatments. For them, chronic diseases offer a far greater reward for their hard earned research: diseases such as HIV where the anti-retrovirals are needed lifelong: cholesterol lowering medications, cancer treatments, blood pressure medications are all well funded as they need long term medication and provide the opportunity of long term profits too.

But before we seriously criticize Big Pharma too much, it should also be noted that they don’t receive too much Governmental incentive to go out on a limb and research new drugs, which can often take 10 years or so to bring to market and cost multi-millions of dollars in the process. Until Governments worldwide realize that the costs of dealing with rampant, multi-drug resistant bacterial infections is far more than targeted research, then we could be returning to a  pre-antibiotic era.

But one of the things that we humans have is wit and insight, and we are learning to exchange information with each other almost as seamlessly as our bacterial co-habitors! All of us are a part of the equation when it comes to solving this problem. Awareness of the magnitude of the problem is the first step and then each of us committing to good personal hygiene in order to reduce the transmission of some of these infectious diseases. Routine vaccination programs have led to dramatic decreases in childhood deaths from entirely preventible diseases and we need to keep up the rates to those already proven programs.
Should a trip to the Doctor result in the need for an antibiotic, then we should ask whether it really is appropriate and if so then we should complete the full course - as shortened courses can raise the risk of bacterial resistance. We should never use someone else’s antibiotic for our illnesses - because in effect that means that they will end up with a shortened course of treatment, and you may be taking a completely inappropriate antibiotic too! Always seek medical advice for any treatment that might be necessary.

Finally, one of the theories that might account for some of the current antibiotic resistance is that we take medications by mouth and they enter our gut tube which is home to a vast array of symbiotic bacteria who do us no harm at all. By disturbing their balance through the introduction of such chemicals, their pooled genetic history can allow them to swap information and quickly work out how to survive such a challenge. If this information is then passed onto the infecting organism, then antibiotic resistance is established. One recent researcher has noted that when antibiotics are given by injection, antibiotic resistance is much slower to develop.
It’s through such simple observations and imaginative thinking that we might be able to face down the impending storm: or to use the words of Dr Joshua Lederberg the Nobel Prize winner, “The future of humanity and microbes will likely evolve as… episodes of our wits versus their genes”

The Podcast of this Blog will shortly be on iTunes along with others recorded for Puggle FM the family friendly site.

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1 comment:

Rebecca Wollstonecraft said...

nice to see someone sharing my enthusiasm for procaryotes!