Bacterial hideouts from fingertips to toilet seats
Your hands are great for lots of things, like gripping, tapping, and feeling subtle textures under your fingertips. They’re also great at growing bacteria, with most people’s hands skin carrying hundreds to thousands of bacteria at any given moment. Washing with soap can make a difference there, but it turns out that our fingernails are particularly wonderful petri dishes, protecting germs from even a diligent scrubbing. Samples under a fingernail are likely to turn up with hundreds of thousands of bacteria per finger in this subungual region. With this much microfauna under our nails, is there much we can do? Is it even worth worrying?
Which fingernails are bacteria’s favorite?
There’s likely not a lot to be done about the microbial zoo under your nails. While doctors and surgeons regularly wash their hands, particularly sensitive procedures usually demand some kind of barrier, like gloves. For more mundane activities each day, you can make your fingertips a bit less attractive to bacteria, although some folks may feel it’d be at the cost of less attractive nails. Samples of nurses found that fake, press-on nails were often home to more microbes, partially because of their length providing a larger protected space, but also because their owners were less likely to wash them. Painted nails posed less concern, even in scratches or nicks that could have potentially been another nook for bacteria. So color is fine, as long as the nails aren’t too long and don’t keep you from washing.
Not just the numbers
Keeping track of bacteria counts is one thing, but since nearly every surface you come in contact with has bacteria on it, numbers may be misleading as far as health goes. You could have a ton of benign bacteria on your knuckle without concern, and it may actually help prevent more worrisome pathogens from finding a patch of skin to take hold of. The real issue is a bit like worries about other “dirty” surfaces, like floors or toilet seats: what kinds of bacteria are present?
For what is hopefully a more extreme example than your fingertips, toilet seats often make people fret about germs, but they’re not really home to a wide variety of bacteria. The biggest worry is usually that someone or something will bring in Vibrio cholera, which can be passed through feces or dirty water, and can lead to illness or death. However, if you’re reading this, odds are this isn’t a concern for your local toilet seat, or your fingernails. This isn’t to say that you can assume all fingernails are safe though— if you’ve been exposed to pathogens like the nurses involved in the above studies, or say, my kids booger-covered fingers when they have a cold, then nails can be a point of transmission. Just wash up with soap as best you can.
Source: What lives under your fingernails? by Jason G Goldman, BBC Future