When a patient has a bacterial infection, they get prescribed antibiotics. But more and more often these drugs are not working because pathogens have developed defense mechanisms against them.
Antibiotics are substances that kill bacteria or stop them from reproducing.
Many antibiotics can be found in the natural world, like penicillin, for example, which some mold fungus species produce to protect themselves from bacteria.
Others are created in a lab or modified chemically to improve their effectiveness.
How antibiotics operate
Penicillin damages bacteria's cell wall synthesis. With a perforated cell wall, the pathogens aren't viable anymore and burst.
Other drugs prevent single-cell organisms from producing proteins they need to survive. Yet other substances block the transport mechanisms in the cell wall, so that the cell's natural equilibrium collapses.
There are also antibiotics that inhibit the pathogens' proliferation. After a while, the remaining single-cell organisms die off without new ones coming up to take their place.
Bacteria reproduce very quickly and are able to rapidly adapt to new environments with new dangers - one of which is antibiotics. Bacteria do their utmost to develop defense mechanisms against these substances, which are of course incredibly harmful for them.
One of these mechanisms is a modification in their genetic material, which helps them to create new, helpful proteins. These proteins cut the antibiotic molecule into pieces and render it innocuous. Or the bacteria modify their cell wall in a way that the antibiotic cannot get inside the cell anymore.
The pathogen also frequently changes the receptor the antibiotic used to dock onto. The bacteria then produce another protein, which takes on the same tasks in the cell, but is immune to the anti-bacterial substance.
Resistance is increasing
When bacteria have found such a mechanism against an antibiotic, they pass on their modified genetic material to all their descendants. Bacteria can even exchange genetic material by simply touching each other. That's how resistance keeps spreading further and further. Many pathogens are even immune to several antibiotics.
These dangerous pathogens include the methicillin-resistant Staphylococcus aureus MRSA, which is resistant to a large number of available antibiotics. The Deutsche Gesellschaft für Krankenhaus Hygiene (German Society for Hospital Hygiene) estimates that significantly more than 5,000 patients a year die from the consequences of an MRSA-infection.
To contain resistance, it's important to not use antibiotics excessively, but only when it's absolutely necessary. Additionally, patients should never stop taking them before the cycle is finished.
For emergencies, there are also "antibiotics of last resort," which doctors only use in critical cases. Because they are used so rarely, bacteria haven't had a chance yet to develop defense mechanisms.
Research is supposed to prevent the pipeline of effective antibiotics from drying up. The only chance to thwart resistance long-term and win the race against the bacteria is to constantly develop new antibiotics that the pathogens don't know yet.