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Understanding antibiotic resistance
Understanding antibiotic resistance

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2 Antibiotics

Antibiotics are chemicals which kill bacteria, that is they are bactericidal, or inhibit bacterial growth, that is they are bacteriostatic. They are produced naturally by soil-living bacteria and fungi in order to stop rival bacteria competing for nutrients and other resources. Antibiotics specifically target bacteria – a characteristic that humans have exploited for their own advantage to manage infectious diseases.

Narrow spectrum antibiotics affect only a few bacterial types. Broad spectrum antibiotics affect a wider range of bacteria.

  • In Section 1 you learned about the different phases of bacterial growth. Most antibiotics target the exponential phase of growth. Can you suggest a reason for this?

  • The exponential phase is when bacterial cells are at their most active, continually growing, dividing and forming new cells. The various metabolic processes which underpin this period of growth – such as the synthesis of DNA/RNA, proteins and the cell wall – are good opportunities for antibiotics to disrupt and/or kill cells.

You will learn how antibiotics work in Week 2.