Antibiotic-Resistant Bacteria

• Antibiotic-resistant bacteria


  Bacteria that have evolved to be less affected by a particular antibiotic
• The discovery of antibiotics was a huge benefit to medicine, but they might not be a permanent solution
• How bacteria become antibiotic-resistant

  1. Bacteria develop random mutations in their DNA

  2. Mutations can lead to changes in the bacteria's characteristics, e.g. being less affected by a particular antibiotic

  3. This can lead to antibiotic-resistant strains forming as the gene for antibiotic resistance becomes more common in the population
• Bacteria can evolve quite quickly because they reproduce rapidly
• Antibiotic resistance


  For the bacterium, the ability to resist antibiotics is a big advantage as it is better able to survive, even in a host who's being treated to get rid of the infection, and so it lives for longer and reproduces many more times
• The gene for antibiotic resistance became more common in the population

  Because of natural selection
• Antibiotic-resistant strains are a problem for people who become infected with these bacteria because they aren't immune to the new strain and there is no effective treatment, meaning the infection easily spreads between people
• Antibiotic-resistant strains


  • MRSA
• MRSA is a relatively common 'superbug' that's really hard to get rid of and can be fatal if it enters the bloodstream
• For the last few decades, we've been able to deal with bacterial infections pretty easily using antibiotics, and the death rate from infectious bacterial diseases has fallen dramatically
• The problem of antibiotic resistance is getting worse, partly because of the overuse and inappropriate use of antibiotics
• Antibiotics don't kill viruses
• The more often antibiotics are used, the bigger the problem of antibiotic resistance becomes, so it's important that doctors only prescribe antibiotics when they really need to
• Antibiotics don't actually cause resistance, they create a situation where naturally resistant bacteria have an advantage and so increase in numbers
• It's important to take all the antibiotics a doctor prescribes for you, as taking the full course ensures all the bacteria are destroyed, which means there are none left to mutate and develop into antibiotic-resistant strains
• In farming, antibiotics can be given to animals to prevent them becoming ill and to make them grow faster, which can lead to the development of antibiotic-resistant bacteria in the animals which can then spread to humans
• The increase in antibiotic resistance has encouraged drug companies to work on developing new antibiotics that are effective against the resistant strains, but the rate of development is slow and it's a very costly process