It’s a familiar story, especially from childhood: you were laughing happily and going far too fast on your bike, scooter or running bike, and suddenly you’re lying on the hard asphalt. The loud screaming of injured children then attracts the adults. One is lifted up and sat down and admires a little bit frightened, a little bit fascinated by the bleeding knee. A graze wound. Off you go home to wash it out, disinfect it and plaster it.
In adulthood, abrasions occur less frequently, but instead one might take more antibiotics. Tonsillitis is treated with them, but also bacterial infections of the skin. Sometimes you wonder: Even though the difference is intuitively obvious – one you spray on the wound, the other you swallow – , you still might wonder sometimes: What is the difference between an antiseptic and an antibiotic? And when is which one used?
Antibiotics are naturally formed metabolites of fungi or bacteria that inhibit the growth of other microorganisms or kill them, even in small amounts. Although the same requirements are placed on antibiotics as on antiseptics, the purpose of their invention is somewhat different. Developed in early 1910, they were intended to treat bacterial diseases systemically.
Although the name and their origin refer to naturally formed substances, antibiotics were partly produced synthetically shortly after their discovery and are fully synthetically produced today. Antibiotics are mainly used systemically, but can also be administered locally in individual cases, although this is generally not recommended due to an increased risk of allergic reactions and the facilitated formation of resistance.
Due to their systemic effect, antibiotics also have systemic side effects. Nevertheless, they are used to combat a specific germ and thus have a clearly defined target. In doing so, they use structures of bacterial cells that do not occur in human cells. As a result, they are generally well tolerated and do not damage human cells. However, if used incorrectly or frequently, bacteria can develop resistances that prevent them from being combated with antibiotics, which is why they should not be used lightly.
A group of highly active antimicrobial peptides, also known as endogenous antibiotics or defensins, has not yet been discovered for very long. These are found, for example, in neutrophilic granulocytes and in intestinal mucosal cells. However, they have only the original definition in common with conventional antibiotics.
Antiseptics are disinfectants intended to prevent wound infection and the associated further sepsis. Accordingly, antiseptics – unlike antibiotics – are not applied systemically but exclusively locally and usually externally. Disinfectants are intended to be bactericidal or bacteriostatic, as well as fungicidal, and to reduce the amount of bacteria and germs in the wound to a possible minimum by killing or destroying them. Typical examples of antiseptics are alcohols, high quality cetrimide or triclosan.
Unlike antibiotics, antiseptics also act in principle on human cells. They adhere to cell walls or cell membranes and inhibit metabolic processes there, as well as toxins and enzymes, leading to cell death. Since this mechanism is relatively unspecific, no targeted counter-reactions of the cell are to be expected and resistance is almost impossible.