Mycoplasma: The Only 4 Letter Word I Don’t Enjoy Shouting

Blog entry

Picture this, dear scientist: You just got your reviews back from Nature. After sitting on it for 6 months, the editors send your work back to you with great news: You’re going to have your first Nature paper!

Of course, after you do the prescribed sets of experiments your esteem peers outlined for you. 

Normally, that’s not a big deal but lately, your cells have been acting squirrely and they seem to be dividing slower, differentiating less robustly, and seem to be overall…crappy. Is it time to start changing serum, growth factors, medium and pen strep? Not necessarily. It could be that your cultures have succumbed to the dreaded Mycoplasma

“Mycoplasma” refers to a genus (which is why I have it italicized) of bacteria, that doesn’t have a cell wall and is known to spread rapidly once it takes hold in your cell culture room. Now here’s the fun part: While they can establish themselves quickly, they don’t divide quickly. This is important because the slow division rate helps keep them from making the medium turbid (cloudy), and since we all are taught to look for cloudy medium when we suspect a bacterial infection, Mycoplasma infections can go undetected for a long time. As if that wasn’t enough to put your boxers in a bunch, our new friends (who will now be referred to as “MP”) are also antibiotic resistant, thanks in large part to their lack of a cell wall. Furthermore, MP infections have known to result in drastic changes in a cell population’s overall physiology because they also figure out how to bind the cells and steal their nutrients…Kinda like a tapeworm on the cellular level.

Yikes! So now what? Well, you could get the bleach and resubmit your work to another journal, and hope the reviewers accept it as is. Alternatively, you can try the experiments with the MP in your cultures and hope for the best, which is so outrageously irresponsible that I’ll assume none of us will do that. The truth is, you’ll probably need to break out the bleach and get rid of all suspected affected cultures. Then, start over again, after you’ve done a thorough cleaning/sterilization of your cell culture room. Yay. Hooray for science…

But are you at risk? Yep. You are. Studies indicated that something on the order of 15% of labs have MP infections, and if you happen to be reading this from the Czech Republic, you may be majorly screwed. Why? Because one study reported that 100% of labs that didn’t specifically test for MP, had it……100%! Egads! Plus, studies done in the US were done using labs that actively test for MP. The actual number can be higher since vastly more labs DON’T test for it. Herein lines a lesson: Make sure your collaborators can prove to you that they tested for MP and that the cells they sent you don’t have it. And, as a courtesy, you ought to do the same if you are sending cells to YOUR collaborators. So, do yourself a favor before the newbies show up in your lab this fall. Test for MP and remind everyone that proper aseptic technique will save them from buckets of reagents and tons of time, and maybe a few hairs. I know i blame MP for the striking lack of hair on the top of MY dome!


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