Is it true that saliva disinfects wounds? Not in the strict sense of the term

Licking a wound will not help you prevent an infection because the saliva does not disinfectin the strict sense of the term. Yes, that’s right, saliva has the job of protect your mouth and the oral cavity from pathogenic microorganisms and in fact we can find them inside it enzymes and molecules that they kill bacteria. But we cannot identify it with a actual disinfectant, like those used on wounds. This is because despite its defensive action, they are also present in the saliva different bacteria: those that normally live in the mouth can be dangerous if transferred to an open wound; others, however, are pathogenic in themselves, such as the bacterium mononucleosisthe so-called “kissing disease” which is transmitted through saliva. We are studying how to exploit the healing qualities of saliva even outside the mouth, but only after having appropriately treated it: sterilization is an obligatory step to remove bacteria and guarantee safety. So, even if we see our cat licking itself to soothe the pain of its wounds, let’s remember that the famous saying “lick your wounds” to heal from a disappointment is just a metaphornot a medical indication.

What is a disinfectant and what is saliva: what does it contain

For disinfectant means a product, chemical compound or process that has the ability to destroy or inactivate pathogenic microorganisms on surfaces or on our skin. Obviously, different disinfectants are used for skin and surfaces! In the case of skin wounds it is best to use antiseptic disinfectants such as hydrogen peroxide or those based on chlorhexidine and iodineavailable in any pharmacy or parapharmacy.

It may seem like a trivial question, but the saliva it is a liquid produced by our body, much more interesting than you might think. We produce approximately 1 – 1.5 L per day and it has a function lubricantbegins the digestion process, promotes the maintenance of healthy tooth enamel and… protects us from attacks by pathogens.

Mainly composed of waterfall (99.5%), inside we also find growth factors and molecules like istatins which help repair wounds and enzymes which begin to break down the food we ingest. Remember when we were children they told us to chew well before swallowing? Well, it wasn’t just to keep us from choking on biscuits.

Furthermore, it contains other molecules that kill bacteria in a thousand different ways. The mucins prevent bacteria from adhering to the oral mucosa, lactoferrin “steals” iron from microorganisms which cannot survive without it. Enzymes like lactoperoxidase they produce a molecule (hypothiocyanate) which inhibits metabolic processes necessary for the life of pathogens; and lysozyme which degrades the cell membrane of bacteria. But that’s not all!

Saliva also contains bacteria

Wait a minute, if there are molecules that kill bacteria, then saliva is a disinfectant! Things are more complicated than they seem, because saliva is also a receptacle for bacteriasome good and commensal (i.e. naturally present in the oral cavity and part of the salivary and oral microbiota), others instead pathogens.

Among the bacteria that are part of the oral and salivary microbiota we find both Gram positive bacteria such as Lactobacillus, Bifidobacterium And Streptococcus that Gram negative like Neisseria, Fusobacterium And Prevotella. In fact, according to a study on microbiome (therefore on the genetic heritage of the microbiota, which is instead the set of organisms: a bit like “human genome” means “human population”) the three genera most present in saliva are Streptococcus, Neisseria And Prevotella.

Transferring these bacteria from the mouth, which is their home, to a wound, perhaps even an open one, is not a good idea at all. Even more so if we think that they can be present in saliva pathogenic microorganisms such as the Epstein-Barr virus, responsible for mononucleosis, often known as the “kissing disease”, precisely because it is transmitted mainly through saliva. You will all remember the famous ones droplets respiratory, which has been talked about so much during the pandemic, and which can favor the contagion of various pathologies, for example when we cough. That’s why if you cut yourself, you don’t want to imitate your cat by licking your wound.

A fluid with a lot of potential

However, saliva is a very interesting fluid for its potential uses, as well as for the functions it performs in our body on a daily basis. Various researches are trying to understand how we can exploit to our advantage, and outside the oral cavity, the healing capacity of saliva (but be careful, in studies the saliva is treated first and sterilizedagain due to the problem linked to the bacteria present).

Already today, it is used as diagnostic fluid: it is easy to collect and its composition also reflects our state of health. It is also a reserve of proteinspeptides and, as we have seen, also pathogens, which is why it can be used as a diagnostic tool for some pathologies, as happened for example for COVID-19 with salivary swabs.