Antibiotics are medicines that kill bacteria or stop them from multiplying. They are ineffective against viruses, which is why they do not treat colds or influenza.
How they work
Different classes attack different bacterial structures:
- Cell wall synthesis — penicillins and cephalosporins prevent bacteria from building their walls.
- Protein synthesis — macrolides and tetracyclines block bacterial ribosomes.
- DNA replication — fluoroquinolones interfere with enzymes bacteria need to copy their DNA.
These targets exist in bacteria but not in human cells, which is what makes selective action possible.
Resistance
Bacteria reproduce quickly and mutate. When antibiotics are used, sensitive bacteria die and resistant ones survive and multiply. Resistance genes can also transfer directly between bacteria.
Drivers of resistance include:
- taking antibiotics for viral infections;
- stopping a course early because symptoms improved;
- routine use in livestock farming;
- poor infection control in hospitals.
Why it matters
Resistant infections take longer to treat, require more expensive drugs and cause more deaths. Procedures that depend on infection control — surgery, chemotherapy, intensive care — become more dangerous as effective options narrow.
Responsible use
- take them only when prescribed;
- complete the course as directed;
- never share leftover medication;
- do not press a doctor for antibiotics for a viral illness.
This article gives general information and is not a substitute for medical advice.