Bioprospecting

The new age prospectors - bioprospectors - Drs. Lauren Paul and William Fenical went to the ocean floor to discover anthracimycin, which might be effective against MRSA and anthrax.

There’s an interesting report by the BBC about the recent discovery of a potentially new antibiotic, anthracimycin, that “seems to be” effective against MRSA and anthrax. The antibiotic was extracted from bacteria that had been collected from the bottom of the Pacific Ocean off the coast of California.

But what are scientists doing making the grand effort to dig up bacteria buried in muddy ocean floors? They call it “bioprospecting,” which is the search in far flung places (think of prospecting for gold in the 1800s) like caves, rain forests, and ocean floors, for natural occurring organisms that have medicinal properties. In this case the naturally occurring organism is a kind of bacteria whose medicinal property fights MRSA and anthrax.

The reasons scientists are engaged in bioprospecting in the first place are important to understand. It’s not because it offers them an exciting life and makes for good conversation over a round of beer. It’s because, contrary to conventional thought, most drugs are not made from scratch in the lab. They’re found in nature and “refined” for popular use in the lab. For example, most antibiotics are extracted from tiny creatures found in the soil. And if you look at the 10 best-selling drugs last year – for things like cancer, arthritis, heart disease, and so on – you find that 7 of those drugs come from nature, not the lab.

But there’s a problem. Why are infectious disease scientists having to scour the ends of the earth to find compounds with antibiotic properties? If most of them are found in the soil, why can’t they just go and dig up the backyard? The answer is because the backyard has been picked clean over a roughly 40 year period beginning in the 1930s. This explains why no new classes of antibiotics have been developed since the 80s; all we’ve done since then is find the same kind of molecules over and over again. In other words, we have long-since picked all the low-hanging antibiotic fruit.

Which leads us to the next problem: antibiotic resistance. Since we’ve been using variations of the same antibiotics for decades now, the bad bugs have figured out ways to beat these drugs thereby rendering them useless. So much so that the World Health Organization announced last week that we’re on the cusp of a worldwide post-antibiotic era in which even common infections and minor injuries which have been treatable for decades can once again kill.

Hence the urgent need for our scientists to pack up their tools and head for some deep cave in an Amazon rain forest to find us some brand new molecule with antibiotic properties. After all, these hidden organisms haven’t been exposed to antibiotic drugs so we know they couldn’t possibly have developed resistance to them … right?

Well that was the theory and a pretty reasonable one at that – until yesterday when we got some bad news: it turns out that most of these exotically located organisms cut off from the rest of the world are in fact already resistant to our antibiotics; it’s as if they were just “born” that way, millions of years ago.

The researchers looked at data from 71 places around the world, everywhere from Antarctic ice to the bottom of the ocean and found antibiotic resistance in every location. A similar study carried out by Dr. Gerry Wright, a self-proclaimed bioprospector and microbiologist at McMaster University in Ontario, dug up bacteria in a New Mexico cave stretching some 1,600 feet underground. He found that, as reported in the New York Times, most of the bacteria were resistant to some antibiotic and others could resist 14 commercially available antibiotics. In other words, antibiotic-resistant bacteria are not just the product of modern medicine, they’re an ancient part of nature.

So if we’ve pretty much found all the molecules in nature that have antibiotic properties and the once promising hope of bioprospecting is not only coming up empty but is uncovering a world full of organisms already resistant to our antibiotics where does that leave us? In polite terms we’ll just say we’re not sure, other than to observe that no antibiotic cavalry seems likely to be coming to our rescue any time soon.

As for the discovery of anthracimycin, that rare and recent bioprospecting success story – it’s still undergoing testing to see if it can be developed as a drug for general use.

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