Livin' on the MDedge

Lack of food for thought: Starve a bacterium, feed an infection


 

A whole new, tiny level of hangry

Ever been so hungry that everything just got on your nerves? Maybe you feel a little snappy right now? Like you’ll just lash out unless you get something to eat? Been there. And so have bacteria.

New research shows that some bacteria go into a full-on Hulk smash if they’re not getting the nutrients they need by releasing toxins into the body. Sounds like a bacterial temper tantrum.

Can you spot the hangry cell? Rosenthal et al.

Can you spot the hangry cell?

Even though two cells may be genetically identical, they don’t always behave the same in a bacterial community. Some do their job and stay in line, but some evil twins rage out and make people sick by releasing toxins into the environment, Adam Rosenthal, PhD, of the University of North Carolina and his colleagues discovered.

To figure out why some cells were all business as usual while others were not, the investigators looked at Clostridium perfringens, a bacterium found in the intestines of humans and other vertebrates. When the C. perfringens cells were fed a little acetate to munch on, the hangry cells calmed down faster than a kid with a bag of fruit snacks, reducing toxin levels. Some cells even disappeared, falling in line with their model-citizen counterparts.

So what does this really mean? More research, duh. Now that we know nutrients play a role in toxicity, it may open the door to finding a way to fight against antibiotic resistance in humans and reduce antibiotic use in the food industry.

So think to yourself. Are you bothered for no reason? Getting a little testy with your friends and coworkers? Maybe you just haven’t eaten in a while. You’re literally not alone. Even a single-cell organism can behave based on its hunger levels.

Now go have a snack. Your bacteria are getting restless.

The very hangry iguana?

Imagine yourself on a warm, sunny tropical beach. You are enjoying a piece of cake as you take in the slow beat of the waves lapping against the shore. Life is as good as it could be.

Then you feel a presence nearby. Hostility. Hunger. A set of feral, covetous eyes in the nearby jungle. A reptilian beast stalks you, and its all-encompassing sweet tooth desires your cake.

Wait, hold on, what?

As an unfortunate 3-year-old on vacation in Costa Rica found out, there’s at least one iguana in the world out there with a taste for sugar (better than a taste for blood, we suppose).

Iguana on the beach Ulrike Mai/Pixabay

While out on the beach, the lizard darted out of nowhere, bit the girl on the back of the hand, and stole her cake. Still not the worst party guest ever. The child was taken to a local clinic, where the wound was cleaned and a 5-day antibiotic treatment (lizards carry salmonella) was provided. Things seemed fine, and the girl returned home without incident.

But of course, that’s not the end of the story. Five months later, the girl’s parents noticed a red bump at the wound site. Over the next 3 months, the surrounding skin grew red and painful. A trip to the hospital in California revealed that she had a ganglion cyst and a discharge of pus. Turns out our cake-obsessed lizard friend did give the little girl a gift: the first known human case of Mycobacterium marinum infection following an iguana bite on record.

M. marinum, which causes a disease similar to tuberculosis, typically infects fish but can infect humans if skin wounds are exposed to contaminated water. It’s also resistant to most antibiotics, which is why the first round didn’t clear up the infection. A second round of more-potent antibiotics seems to be working well.

So, to sum up, this poor child got bitten by a lizard, had her cake stolen, and contracted a rare illness in exchange. For a 3-year-old, that’s gotta be in the top-10 worst days ever. Unless, of course, we’re actually living in the Marvel universe (sorry, multiverse at this point). Then we’re totally going to see the emergence of the new superhero Iguana Girl in 15 years or so. Keep your eyes open.

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