Mad About Science: Wild Bacteria

By Brenden Bobby
Reader Columnist

When we think about bacteria, we think about soaping it off our bodies as quickly as we can. A clean body is a body without bacteria.

A closeup view of MRSA. Courtesy photo.

That’s a load of bacteria that comes out of a bull.

Humans have a bare minimum of one bacterium for every cell in their body. Our intestines alone are essentially big tubes stuffed full of bacteria. If we didn’t have all of those microbes swimming around our fecal expressways, we would get stuffed full of food that just rots inside of us and kills us, full stop.

Bacteria aren’t always bad. In fact, bacteria are seldom bad unless you just had surgery, have an impaired immune system or managed to damage your skin doing a sweet kickflip at the park. Studies have shown that exposure to bacteria actually helps our immune system effectively resist that bacteria later, with some exceptions.

MRSA, or Methicillin-resistant Staphylococcus aureus, is what happens when your run-of-the-mill Staphylococcus bacteria become immunized to antibiotics from overexposure. This can happen for a number of reasons, but the primary reason for the existence of MRSA is people using antibiotics every time they get sick. Things like the flu and the common cold are caused by viruses, which are completely unaffected by antibiotics, and using antibiotics to treat the cold and flu will kill lots of beneficial bacteria in your body, while also helping the bad ones evolve and adapt to resist those drugs in the future.

Most of us are aware of the bacteria that impact our lives the most: E. coli, Salmonella, Staphylococcus and other gross germs that keep us away from public restrooms, but these aren’t even a drop in the bucket compared to what’s out there.

Before penicillin was invented in 1928, did you know that doctors and battlefield medics used bacteria as a disinfectant? There is documentation of battlefield medics during the Civil War using the bacteria Photorhabdus luminescens to treat wounds. Keep in mind: Hand washing was a relatively new phenomenon in the mid-1800s, and bacterial research was pretty cutting edge stuff at the time. Doctors during the Civil War called it “Angel’s Glow,” because the bacteria is bioluminescent and if treated wounds were glowing, it meant they were healing properly. 

The reason Photorhabdus luminescens was an effective antibiotic, despite being bacteria itself, is the mechanism by which it reproduces: It will take up residence somewhere, generally within an insect, and secrete an agent that kills most bacteria around it to minimize competition and reproduce.

The astounding lengths that most bacteria go to survive is what makes them stand out in the natural world. While most people would immediately think of MRSA, another bacteria is not only far more resilient, but able to regenerate on its own. Gloeocapsa magma is a type of bacteria that existed on the outside of the space station for more than a year. Under these conditions, solar and cosmic radiation constantly barrages anything trapped in the environment, stripping electrons from matter and turning DNA strands into bits of organic confetti, but G. magma has an uncanny ability to repair its own DNA, even while sizzling on the sunny side of the ISS.

Intense radioactive resistance isn’t a trait restricted to G. magma, as we’ve discovered a bacteria in our backyard that not only resists radiation, but thrives in it. 

Deinococcus radiodurans is an intense little microbe currently living in the Hanford nuclear waste repository. When tested in a lab, scientists discovered it could survive radiation levels up to 2,000 times more intense than what would kill a human. D. radiodurans has the specialized ability to isolate DNA damaged by radiation in a special cell compartment and then fuse it with healthy DNA in a remarkably short amount of time: 24 hours or less. This puts cockroaches as apocalyptic survivors to shame, but what’s most remarkable is that D. radiodurans isn’t the only bacteria capable of surviving and thriving amidst such intense radioactivity. Scientists have discovered several other forms of bacteria that are taking on these characteristics and thriving in waste dumps. I suppose it’s calming to know that even in the face of nuclear devastation, not all life on Earth would be lost.

Some bacteria make things beautiful by doing things that are terrible. Scientists have found a slimy bacteria that gather in colonies resembling oozing blobs of snot and live in abandoned mines filled with toxic heavy metals like mercury. Acidithiobacillus eats away minerals like sulfur and iron, then excretes sulfuric acid as waste. The acidic waste reacts with limestone to create shimmering crystals that make the walls of caves shine. It’s beautiful if you ignore the acid-pooping snot blobs hanging off the walls.

The world is filled with weird and wonderful bacteria. Several precious gems found on Earth wouldn’t be possible without the help of bacteria. The next time you cover an entire public bathroom in paper towels to avoid touching germs, just remember this important fact: Your phone is covered in more bacteria than a public toilet seat, 10 times over.

You’re welcome.