Wouldn't Using All This Hand Sanitizer and Washing Hands 20 Times a Day Eventually Develop a More Resistant Bug?
No hand washing and hand sanitizing aren’t likely to develop a more resistant bug. Here’s why.
No, This Isn't About Antibacterial Soap
When you wash your hands, you are not killing germs or even trying to kill germs. Well, okay, before you go and write a tirade into the comments about antibacterial soap, I will go ahead and acknowledge that yes, there are soaps available that have chemical additives meant to kill bacteria. But these additives do not offer any proven benefit over simply washing your hands with plain old soap and water.
The Mechanics of Hand Washing
The primary way that hand washing helps to reduce germs on your hands is by mechanical separation of the germs from your skin and down the drain. You literally scrub them loose, and by dilution with water, they float away. Soap is useful here because it has a hydrophobic and hydrophilic end. The hydrophobic side of the soap molecules, since it is repelled away from water, tends to grab onto any other particles that might be floating in the water—whether they are dirt particles, bacteria, or viruses. The bacteria or germs are then completely surrounded by soap molecules, trapped in little capsules of soap.
However, the outside of these soap capsules is the hydrophilic end of all these soap molecules. This side of the molecules is attracted to the water and sticks to it rather than anything else. What you arrive at is a capsule of soap molecules where whatever is trapped inside is bonded to one end of the soap, and the outside of the capsule is basically glued to the water. You have a tiny force field that keeps the wee beasties trapped in the water and pulled from your hands. Since the bugs aren’t being killed by the soap, there isn’t anything for the bugs to evolve against.
Hand Sanitizers: A Different Story
Hand sanitizers are another story. They aren’t trapping germs in a little bubble and then removing them. How an alcohol-based hand sanitizer works is by denaturing the cell membrane in some way. There are already some bacteria that are resistant to alcohol, but at the high concentrations used in hand sanitizers, the alcohol is too potent to readily resist.
Many bacteria and viruses have membranes that contain lipids (fats) which the alcohol dissolves, tearing up the membrane in the process. For some that don’t, alcohol denatures proteins, and since the cells rely on proteins having very specific foldings to remain functional, this tends to render the membrane dysfunctional, which kills the cell.
This isn’t to say that it is impossible for a virus or bacteria to become resistant to alcohol. However, the way it might evolve this resistance takes a lot of evolutionary energy. For instance, an antibiotic might target and attach to a specific protein on the cell membrane of a bacteria and then tear the membrane apart. If that cell has a slight mutation where that membrane no longer has that protein present, then it will be resistant to that antibiotic. By contrast, the entire membrane will have to evolve changes to become resistant to alcohol, which requires a lot of smaller changes. Any one of which won’t particularly be beneficial to survival of the cell on its own. This means that there are some pretty large amounts of random mutation that would need to take place to get a sufficient number of changes where a cell might survive better and pass on its resistance.
So hand washing won’t lead to superbugs, and the use of hand sanitizers may lead to some alcohol-resistant bugs, but the likelihood of this sort of resistance developing is far less than antibiotic resistance, and even antibiotic resistance took many years to develop. So the short-term risk is minimal.