The bacteria in your belly Pt. 3 – Disrupting the balance

In the previous two posts we have established how the microbiome is established and then the pressures the host puts on it to maintain a balance between the required functions and the commensal bacteria providing them. In this post I want to look a little deeper at what happens if this balance is disturbed or never properly forms at all.

Why dont we just leave it to antimicrobials?

In the last of my vaccine sub-series (the others can be found here, here, here and here) I wanted to talk about why vaccines trump therapeutics every time or at least just a few reasons why.

Something I hear occasionally when talking about vaccines is that they are not required as we have drugs to deal with sickness. It’s true we have developed everything from cold and flu meds to antibiotics and chemotherapy but vaccines are still, in my opinion, the greatest advancement in public health after improved sanitation.

The Wednesday Post (1/9/10)

Enough of vaccines for a moment. I want to talk about frogs, frogs and antimicrobial agents.

Normally I find it hard to remain interested in anything with a central nervous system but recently two frog related stories have caught my eye. First was this little dude.

This little guy is called Microhyla nepenthicola <http://upload.wikimedia.org/wikipedia/commons/d/d4/Microhyla-nepenthicola.jpg&gt;

Are you kidding me, that thing is tiny. Sometimes its hard to separate what ‘should be big’ like animals with skeletons and brains etc from what ‘should be small’ – anything that can be measured by ‘the number that could fit on the end of a pencil’. It turns out we have known about them for a while but they were incorrectly classified by a museum who thought they were juveniles of a different species, easy mistake to make I guess. They live in the pitchers of the plant Nepenthes ampullaria and the tadpoles develop in the watery discharge inside the pitcher until they can climb out. Awesome.

As interesting as this little guy is it’s hardly a disease or even remotely disease-y enough on its own. I only mention it was the first of two frog stories that caught my eye.

At a meeting of the American Chemical Society last week a group of researchers from the United Arab Emirates University presented some data showing they had collected and analysed frog skin compounds that elicited an anti-microbial effects from a wide range of species. They have been able to isolate over 200 novel compounds in only a year, which suggests that there are hundreds more compounds to find.

Specifically what they found was a number of potent anti-microbial peptides. Most organisms produce something of this nature and in fact humans produce our own AMP’s, but, human pathogens evolve to evade human defences so the sudden potential availability of new AMP’s may help in the production of new drugs for the treatment of human diseases.

The next step is to take these new compounds as they are identified and check for toxicity to human cells and to make any changes that can mitigate toxicity without affecting the anti-microbial potency. With some compounds already showing promise in regards to bacterial species like the infamous ‘Golden Staph’ frog based therapies might not be too far fetched and with any luck not too far away either.

In the long run the problem with developing these therapies might be us as it’s estimated that many frogs species are becoming extinct and humans are certainly responsible for some of this.

Unless you’re not a nature and biology lover already perhaps this provides a good enough reason for you to protect the environment. As clever as we are at experiments and drug design nature has undoubtedly done it somewhere before. Nature’s experiments are better designed and take place over a longer time frame.

So protect the frogs, newts, salamanders and all animal life if only on the off chance they might one day save your life.

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References

Blaustein, A., & Kiesecker, J. (2002). Complexity in conservation: lessons from the global decline of amphibian populations Ecology Letters, 5 (4), 597-608 DOI: 10.1046/j.1461-0248.2002.00352.x
Smet, K., & Contreras, R. (2005). Human Antimicrobial Peptides: Defensins, Cathelicidins and Histatins Biotechnology Letters, 27 (18), 1337-1347 DOI: 10.1007/s10529-005-0936-5

Scientific Casualties – Infectious disease research can be life threatening

Before this weeks post I would like to make an announcement. At this stage I am claiming victory in the debate. You can check out the results on the poll itself here. First I would like to thank myself for putting up such an amazing argument. I would also like to thank Thomas for putting up an insufficient fight, I’ll save some cake for you buddy. I would like to thank my wife and our dogs whose love and support get me throu………..<music plays me off stage>.

I don’t want to sound like I’m brave or a hero or anything but each and every day I, alongside my lab-mates aka ‘the league of extraordinary scientists’, stare down pathogens like S. pneumoniae, E. coli, S. flexneri and L. monocytogenes. We go into battle to try and work out how it is that we can tackle these bad guys on a global scale, developing vaccines and anti-microbials or simply understanding their weaknesses better.

So how do we protect ourselves from these harbingers of death in the lab? A gown, gloves and glasses when appropriate and ethanol on everything all the time to ensure it’s sterilised regularly. Really doesn’t seem like much of a barrier when I think about it.

Thomas wearing his lab coat to protect himself from his work… Thomas. Are you in a bar? Bad Thomas!

In some cases we specifically work on weakened strains to help protect ourselves further but we do rely heavily on our ability to handle these bacteria carefully and with common sense. However, despite all the precautions we take in the lab I’m reasonably sure some of us would be carrying the bugs we work on.

Viruses Vs. Bacteria – Debate Rebuttals

<http://www.flickr.com/photos/walkn/3314689121/&gt;

 

Thomas and I will present our rebuttals below. Feel free to read through them, the original posts which can be found here and here. After taking in both arguments vote for the winner on our first poll. Or just skip to the poll, it’s your vote to cast as you wish

P. aeruginosa, Biofilms and Honey

In what will be the first of a few articles inspired from my recent soirée in old Sydney town I want to talk today about biofilms. Biofilms were a focal point for the conference and I got to hear a lot about who makes them, why they are made, the maturation of biofilms, what happens when opposing species biofilms interact, biofilms underwater, biofilms on organic material and on man-made surfaces, how we can kill organisms within them, how we can break-up a biofilm and honey. But maybe it’s worth starting at the beginning. What’s a biofilm?

Antibiotic-associated colitis – Poo transplants!

We’re running out of antibiotics. From methicillin-resistant Staphlycoccus Aureus (also known as Golden Staph) to multi-drug resistant tuberculosis (which is now at the highest levels we’ve ever seen), we are wading in a fast-rising pool of resistant pathogens.

Ampicillin is feeling a bit useless now... (Photo taken by Thomas Tu)

And we’re not walking to shore as quickly as we used to; the number of classes of antibiotics being invented are going down each year. Biotech companies find it hard to profit off of any new antibiotics while others are still semi-effective, so do not fund their research. In the end, it is like ditching water in a leaky boat anyway; pathogens no doubt will find a way around whatever new antibiotics we do end up using. So scientists are looking at alternative ways to control infections, one of which I’ll talk about today.

(anti) Disease of the week: Antibiotics – Fighting fire with the gooey bits that come out of other fires

Surprise article from me (bailing James out, as per usual). This is another old On Dit article. Although not technically a disease, antibiotics are much closely related to pathogens than you might think. Plus, I was sick of painting an entirely bad picture of microbes.

Antibiotics have been one of the most successful ways of saving human life ever discovered. Before antibiotics, a person who accidentally cut themselves would fear infections like cancer. An infected wound could mean necrosis of a limb (requiring amputation), septicaemia, multiple organ failure or death. Today, simply taking a pill is enough to avert this.

All hail Lord Amoxycillin, Bringer of cures and Bane of broad-ranged evils! (Side effects of worshipping Amoxycillin include nausea, vomiting, rashes, diarrhea and antibiotic-associated colitis. Those allergic to beta-lactam antibiotics should consider a different Lord.) (Picture taken by Thomas Tu)

A commonly used definition of an antibiotic is “a microbial product or derivatives which kill microbial agents or inhibit their growth”, although now some antibiotics (such as chloramphenicol) can be synthesised completely in vitro. You might wonder why microbes spurt out poison chemicals. It’s a selfish thing. If a bacterium kills all the other bacteria around it, it has more sugar and other resources to grow. So, that bacterium will become more prominent and become the norm in the species. Woo, natural selection! There are over 100 antibiotics, but a lot of them are slight variations of each other and fit into several families.