Most of us say we don’t want to eat meat that has been pumped full of antibiotics, or eat fruit and veg treated with lots of pesticides. So why are we so keen on using such products when cleaning our homes? Dr Anna explains why we don’t really need to use antibacterial products to clean our homes…
I’m sure we have all seen a toddler drop their toy on the floor, pick it up and put it straight into their mouth. There are usually two responses from parents: 1) trying to clean everything before handing it back or 2) something along the lines of ‘it’s fine, let them eat a bit of dirt’. It is understandable that we want to protect those we love, so what do we need to do to clean our homes well? Do we need to create a completely sterile environment to be safe? Or do we need to bother with cleaning at all?
As you may have guessed, there is a balance to be struck between the two. It has been shown that exposure to some microbes during childhood (especially the first few years) is beneficial to development of a healthy immune system. In addition, there’s lots of ‘good’ bacteria around us that contribute to our skin and gut health, among others. The increased use of antimicrobial products and overly clean environments has even been linked with development of asthma and allergies amongst young children. Again, some balance here is advisable, for example washing hands before eating is probably a good idea, but there is no need to use an antibacterial hand wash every time.
What are antimicrobials?
In general, something called a disinfectant (or an antimicrobial/antibacterial agent) does not clean the surface. It will kill bacteria and/or viruses present on the surface, but only when applied according to instructions (often meaning it needs to be left on a surface for 5-15 minutes to be effective). Some (not all) disinfectants are only suitable for pre-cleaned surfaces, as organic matter (such as sweat, soil or fat) may inactivate its antibacterial properties.
Do people need to use an antibacterial spray in their homes?
In general day-to-day life, there is no need to use antibacterial spray on top of cleaning products. However, we understand there are times when you want to reach for an antimicrobial product, for example when someone in the household is ill or immune compromised. In this case, always make sure to read the instructions properly, as you may have to use a different product to clean your surfaces first, before applying an antimicrobial product of your choice. My advice would be to not use these products regularly without a good reason, just as you would not take antibiotics for a cold.
Why killing bacteria can do more harm than good?
Antibiotic resistance is becoming a global problem. Tens of thousands of people die every year from infections where antibiotics have stopped working due to the bacteria developing resistance. The number one cause of this resistance is overuse of antibiotics in healthcare, but also in animal feedstock and water contamination. However, overusing antibacterial cleaning products can also contribute to development of antibiotic resistance.
In general, there are two ways antibacterial products work: non-specific and specific targeting. Using an alcohol spray is an example of non-specific mode of action, and this does not cause any concerns in terms of bacteria developing resistance. On the other hand, when antibacterial agents target specific bacteria, this bacteria can develop resistance. This resistant bacteria (the 0.1% of bacteria left behind) then knows how to survive our cleaning regime and starts breeding to create superbugs in our homes.
The biggest problem is, however, that antimicrobial cleaning products often act in the same way as antibiotics. Once the bacteria develop resistance to a certain biological pathway, it becomes cross-resistant not only to the cleaning product but also to any antibiotic that acts in the same way. If we then get ill because of our homegrown bacteria, the usual antibiotics will not work, as our ‘superbugs’ are now resistant to them. This means we will have to be prescribed stronger antibiotics and/or our illness may last longer and be more dangerous.
If using antimicrobial products doesn’t clean our homes, what does?
As mentioned before, there is no need to keep our homes absolutely spotless. For general cleaning, quite often all you need is a gentle cleaning product containing soap or surfactants, with a bit of help of solvents (e.g. alcohol), acids (e.g. vinegar & lemons) or alkalis (bicarbonate of soda), depending on the stains you are dealing with.
Soap (and surfactants/detergents) can also kill bacteria and some viruses, such as coronavirus. Soap molecules bind to the protective lipid coat of viruses and bacterial cell membranes, and disturb their stability. Together with a bit of physical action (such as rubbing your hands together while washing them, or using a cloth on a surface), the protective membranes are destroyed and the virus or bacteria is killed/removed. The microbes cannot evolve any mechanism to counter this, as it is largely a physical process (with a bit of chemistry), rather than targeted biological reaction. This does not work perfectly, but any microbes that are left over cannot evolve a protective mechanism and become resistant. The next time you clean the surface, they will likely get killed. What’s more, you are also removing the microbes and any dirt from the surface with your cloth.
Counter Clean vs Bacteria & Viruses
What about hand sanitisers?
Hand sanitisers are a special category. They are perfect to use if there is no soap and water available to clean our hands. They do kill more than 99.99% of bacteria and (some) viruses, however they most often use a high concentration of alcohol to do this, rather than use other antimicrobial agents. This means that their mode of action is similar to that of soap, i.e. they kill the microbes in a way that does not allow for any antimicrobial resistance to be evolved. The reason we don’t use hand sanitisers (or products that contain over 70% alcohol) to clean our homes is that they do not smell great, the high alcohol content can sometimes be irritating if applied in large quantities, and it is not actually needed. However, if you need to spray a couple of door handles or light switches in your house after someone ill with a virus touched them, our hand sanitising spray would be a perfect product to use!