How gross are your earbuds?

When you share earbuds, do you ever think about the bacteria that could be on them? We tested 22 pairs of earbuds to see what might be lurking on them. After they incubated in the lab for a few days, we went back to check out the results. Following is a transcript of the video.

Narrator: Do you ever do this? In some ways sharing earbuds is like sharing a Q-tip. Even though you don't use earbuds to clean your ears, you're still shoving them pretty far in there. And earwax can get stuck in the crevices of the earbud so when you share them, you might be trading wax with someone. But is that a bad thing?

Emma: Generally I like to stay away from sharing earbuds.

Abby: I often will do the split earbud thing, where you've got one in your ear and you give it to your friend and you're like, "Here's a cool song. Listen to this with me."

Medha: I just feel bad for whoever has to share my earbuds.

Kara: They can borrow the over-the-ears, but they can't borrow in-buds.

Narrator: To see how gross earbuds really are, we swabbed 22 pairs to get tested for bacteria. We also swabbed two over-ear headphones to see if they were any different. And then we took the swabs to Columbia's microbiology lab.

Dr. Susan Whittier: Now what I'm gonna do is I'm gonna take those swabs and inoculate them onto agar plates. So agar plates are what we use to grow bacteria and yeast and sometimes mold. There's more bacterial cells as part of our body than normal human cells. So we know that they're gonna grow something.

Dr. Sujana Chandrasekhar: It's sort of a dark, moist, warm place- your ear canal. So that's a terrific breeding ground, so if you introduce bacteria or fungus into the outside of your ear, you can propagate the growth of that just by the nature of what our ear canal is like.

Whittier: The red plate is a sheep blood agar plate and it grows all bacteria. And then this is a MacConkey plate and it mainly just grows gram-negative rods. So bacteria that you'd find in poop.

Narrator: In a previous test, Whittier found strains of MRSA and, yep, fecal matter on people's smartphones. We let the earbud samples incubate for about three days and then went back to the lab to check out the results.

Whittier: Two samples were positive for yeast. So that's certainly not something you'd want to share. This is the grossest looking thing we found, the culture that was positive for Bacillus, something we find in soil. I was really shocked we didn't find anything super gross or super dirty. We all have certain bacteria on our skin and most of what we recovered was that. That's a species of Staphylococcus called coagulase-negative staphylococcus. And that's the predominant organism that we have on our skin. So the theory that ear canals may have something a little bit different didn't really pan out because we got the organisms that we would expect as if you swabbed your arm.

Narrator: But two of the samples did grow yeast and one grew a type of bacteria associated with dirt. So even though most of the bacteria found was normal skin bacteria, the yeast was a little off-putting.

Producer: There was yeast on two of them.

Janaya: Oh.

Abby: I don't know what yeast is really.

Dan: I don't feel that bad about that one.

Abby: I think it'd be fine to share my yeast with somebody else.

Chandrasekhar: Yeast is just a nice way to say fungus. And it can cause itching, it can cause swelling, it can cause- in fact I actually just had a patient who had the worst yeast infection in her ears I've seen in ages.

Whittier: So I'm unlikely to start sharing my earbuds at the gym even though these results show that we really didn't find anything too strange or too pathogenic, but that's just me. You know we didn't know what we were gonna find and it turns out that up there were just normal bacteria, but I'd still like to keep my bacteria to myself.

Narrator: While we didn't find anything too gross on any of the earbuds, you still might want to consider rubbing them with an alcohol swab before going from a friend's ear to yours.