Summary
Drugs that kill or inhibit bacteria, such as penicillin, which blocks cell wall synthesis.
In depth
Targets: cell wall (penicillins, vancomycin), ribosomes (tetracyclines, macrolides), nucleic acid synthesis (quinolones, rifampicin) and folate synthesis (sulfonamides). Fleming discovered penicillin in 1928. Broad-spectrum drugs affect many bacteria and can disturb the microbiome.
Bactericidal drugs kill; bacteriostatic ones inhibit growth. Narrow-spectrum drugs affect few species. Combination therapy reduces resistance.
Example: vancomycin treats resistant Gram-positive infections.
The first antibiotic found, penicillin, was discovered by Fleming in 1928 and developed by Florey and Chain in the 1940s. Most are made by soil bacteria and fungi, especially Streptomyces. Spectrum can be narrow or broad, and action is bactericidal (kills) or bacteriostatic (stops growth). Selective toxicity depends on differences between bacterial and human cells.
Antibiotics do not work on viruses, so using them for colds is a waste and drives resistance. Courses should be taken as prescribed; stewardship programmes limit use. New discovery has slowed, with few new classes since the 1980s, though teixobactin, and AI-guided screening to find compounds such as halicin, offer promise.
Common mistake: believing that the body becomes resistant to antibiotics; it is bacteria that become resistant.
Frequently asked questions
What is Antibiotics?
Drugs that kill or inhibit bacteria, such as penicillin, which blocks cell wall synthesis.
Which area of biology covers Antibiotics, and how advanced is it?
Antibiotics is one of the 54 topics in Microbiology. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Antibiotic Resistance Mechanisms, Fungal Pathogens, Bacterial Cell Wall.
Can you give an example of Antibiotics?
Penicillin does not harm human cells because they lack a cell wall.
What should I learn before Antibiotics?
Work through the Beginner topics in Microbiology first, such as Microorganisms, Bacteria, Archaea, then return to Antibiotics. Intermediate topics assume the Beginner vocabulary.
What topics are related to Antibiotics?
The closest topics to Antibiotics are Antibiotic Resistance Mechanisms, Fungal Pathogens, Bacterial Cell Wall, Conjugation. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Antibiotics?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Antibiotics. To practise the whole of Microbiology, use the Microbiology quiz.
How is Antibiotics different from Antibiotic Resistance Mechanisms?
Antibiotics: Drugs that kill or inhibit bacteria, such as penicillin, which blocks cell wall synthesis. Antibiotic Resistance Mechanisms: Bacteria resist drugs by enzymes like beta-lactamase, efflux pumps, altered targets and reduced uptake. Read both side by side and note what each one explains.
What is a common mistake about Antibiotics?
Believing that the body becomes resistant to antibiotics; it is bacteria that become resistant.
How should I study Antibiotics step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Antibiotic Resistance Mechanisms and explain the difference aloud. Finally, take the Microbiology quiz and come back to this page for any question you miss.