Today we have another guest post. This time from Maya, a fellow graduate student at UNC.
Hello there, readers of UndertheC!! My name is Maya Nadimpalli, and I’m a PhD student in Environmental Microbiology at UNC’s School of Public Health. I’ve been taking a great Science Communication class this past semester with some of the marine science graduate students who contribute to this blog. After hearing about how social media is the key to effective communication, I thought I should probably take a stab at this whole blogging thing. I’m excited to be here!
At first appearance, my research is pretty much the opposite of aquatic-themed – I study how certain emerging infectious microbes (such as antibiotic-resistant Staph and the flu) might be associated with factory farming.
Some of you have likely heard or read something about the growing epidemic of antibiotic resistance– it’s a pretty hot topic right now. Antibiotics have been used to treat bacterial infections since the 1940s. Prior to their advent, strep throat could be fatal, ear infections could spread to the brain, and syphilis was treated with arsenic or malaria. Yes, malaria – you read that correctly. Not fun times.
But, for as long as we’ve been using antibiotics to treat infections, bacteria have been developing clever ways to prevent them from doing their job. Genetic code that allows bacteria to survive in the presence of antibiotics – what we microbiologists refer to as “resistance genes” – can be passed by bacteria to their offspring, as well as to other bacteria in their environment. Eventually, these resistance genes can become so common that an antibiotic may become totally ineffective against certain types of bacteria. Unfortunately, this problem is only getting worse – potentially as a result of overuse, or maybe due to improper use and disposal of antibiotics. Take, for example, the alarming news that a gene encoding resistance to every class of antibiotics known to humans was recently found in New Delhi’s tap water. Scary stuff, right? Meanwhile, the number of antibiotics that have been approved for use in humans has steadily dwindled over the past few decades. Could we be returning to those dark times where we don’t have antibiotics to treat bacterial infections, as some have suggested? What is humanity to do?!
One possible solution may lie in….…our oceans. Dun dun dun dun! Didn’t see that coming, did you? To understand this, we first have to take a step back. Where do we get compounds to kill bacteria from in the first place? Well, the answer is….from other bacteria, actually.
Turns out that bacteria are constantly competing with each other for finite supplies of resources. As they process their food, some bacteria (as well as some fungi) are able to produce tiny, toxic by-products that are harmless to themselves, but are poisonous to other bacteria who might be competing for the same energy sources. Nothing like a little poison to stop your competitors in their tracks, amiright? Many of the antibiotics we use today are actually modified from tiny molecules produced by Actinomycetales, a group of bacteria found in the soil.
In the 1990s (about 50 years after antibiotics were mass-produced for the first time), interest in screening soil bacteria for molecules that could be developed into antibiotics began to fade, as we realized we could identify and design new antibiotics ourselves using computers. However, researchers are now beginning to turn back to “natural” methods of antibiotic identification, and many think bacteria found “under the sea” are well worth exploring.
Considering the ocean comprises over 70% of the Earth’s surface, it may be surprising that no one ever thought to investigate marine bacteria before. Actually, when we first began synthesizing antibiotics, we hadn’t yet developed the proper lab methods to characterize bacteria living in the world’s oceans, let alone isolate and analyze the tiny toxins they may be producing. However, in just 60 years, we’ve gone from being unsure that there even were bacteria in the ocean to totally taken aback by the microbial complexity of the Earth’s oceans – estimates now suggest that there are upwards of 1 million bacteria per ml of seawater, and more than 1 billion per ml of sediment on the ocean floor!
And we now have evidence that there may be some very useful bacteria under the sea, too. Remember Actinomycetales, that group of bacteria that live in the soil from which we’ve derived many of the antibiotics we use today? Well, actinomycetes exist in the marine environment, too. Marine actinomycetes are different from their land-loving relatives – some require the salt from seawater to survive, for example. However, researchers have discovered that they may be just as prolific as their soil-based kinfolk in producing tiny toxins that we could develop into new antibiotics. Scientists from the University of California-San Diego, have identified several species of actinomycetes that produce toxins with chemical structures we’ve never seen before. Finding such compounds is rare, and hugely beneficial because bacteria causing human infections will be fully susceptible to antibiotics developed from these new molecules– which is exactly what we want.
In 2013, a group from UC-San Diego isolated a novel tiny toxin which demonstrates the ability to kill anthrax, the infectious bacteria that has previously been used as a biological weapon, as well as the ability to kill methicillin-resistant Staphylococcus aureus (MRSA), which is responsible for more deaths each year than HIV/AIDS in the US (and also the bacteria I study. How cool is that!!
Research in this field continues, and will pick up its pace as we improve our technologies for deep ocean sediment sampling. Right now, it appears that we’ve only investigated a tiny fraction of the actinomycetes living in the ocean, meaning there are a lot waiting out there to be discovered. So in conclusion, good news! There is reason for optimism when it comes to warnings about our antibiotic-free future, where bacteria are kings of the playground and we have no way to defend ourselves against them. For now, stay tune for the next groundbreaking antibiotic discovery – coming from an ocean near you.