These bacteria have evolved to this non-treatable state in response to antibiotics and certain antibacterial substances, but does hand sanitizer also contribute to the superbug problem?
Not usually. Alcohol-based hand sanitizers are not the problem. The CDC recommends using sanitizers (like Purell) that contain at least 60% alcohol, which are the same kind used in hospitals.
Alcohol is an antiseptic agent that kills most bacteria on external surfaces on contact, breaking down the proteins that make up bacteria and some viruses. (Bleach works similarly, but is much more potent - don't put that on your hands.)
Antibiotics, meanwhile, typically target specific aspects of bacteria, and don't just work on external surfaces.
Instead of shattering everything in their path like a hammer, antibiotics are more like keys that fit into very specific keyholes: When they click together, the bacteria are destroyed. But when bacteria evolve to lose those vulnerable characteristics, the key no longer fits - and the newly strong bacteria can survive.
How antibiotic-resistant bacteria come about
Antibiotic-resistant bacteria are the only ones that survive a course of antibiotics. When those resistant traits are then passed on, whole strains of resistant bacteria are created - and can be impossible to kill.
Used properly against non-resistant bacteria, antibiotics should kill all the targeted microbes, not allowing any to survive. Part of the reason doctors say patients should finish their prescription, even if they are feeling better, is because not doing so can leave the strongest bacteria still alive.
Research shows that up to 50% of the time, antibiotics are misused or prescribed, like for patients who have a cold or other viral illness. Such problems can't be helped by antibiotics at all, contributing further to the creation of superbugs.
Another huge contributor to the problem is the widespread use of antibiotics in healthy livestock to make them gain weight faster. This also allows antibiotic-resistant bacteria to flourish, which the CDC says makes everyone less safe.
But antibiotics can be lifesavers, and they do need to be used sometimes. It's the other bacteria-killing products that can be problematic.
Why some products contribute to antibiotic resistance and others do not
Nonalcoholic hand sanitizers, antibacterial soaps, toothpastes, and other home products frequently contain an antimicrobial compound called triclosan or a similar compound, such as triclocarban.
This is a problem.
First of all, there's no evidence that triclosan is effective at preventing illness in the first place, according to the FDA - so it already doesn't do the one thing that it theoretically should.
But even worse, the FDA says research suggests triclosan may lead to hormonal problems and cause bacteria to adapt to its antimicrobial properties, creating more antibiotic-resistant strains. Additional research shows that people with high levels of triclosan in their noses were twice as likely to carry disease-causing Staph bacteria in the nose.
Alcohol-based sanitizers, on the other hand, actually work: They effectively neutralize germs, especially in hospital settings.
They don't work as well if hands are visibly dirty or greasy however, and so handwashing is recommended in those circumstances - but not with antibacterial soap, for the reasons mentioned above. Plain old soap and cool water will do.
Handwashing is also a more effective way to remove some bacteria (including C. difficile) in the first place, which is why people should still wash their hands regularly, especially in hospital settings.
But it's especially important to stop the spread of dangerous bacteria in those medical situations. So in addition to handwashing, using an alcohol-based sanitizer whenever possible is a good idea, particularly before and after interacting with patients.
So go ahead and sanitize away. Make sure to use enough to fully coat your hands, and don't wipe it off.