4-3-15-consequences-of-resistance as

Consequences of Resistance

Consequences of antibiotic resistance

• Antibiotic-resistant strains are a major problem in human medicine

• New resistant strains are constantly emerging due to the overuse of antibiotics

  • By using antibiotics frequently, humans exert a selective pressure on the bacteria, which supports the evolution of antibiotic resistance

• Scientists are trying hard to find new antibiotics that bacteria have not yet been exposed to, but this process is expensive and time-consuming

• Some strains of bacteria can be resistant to multiple antibiotics and they create infections and diseases which are very difficult to treat

• When antibiotics were discovered, scientists thought they would be able to eradicate bacterial infections, but less than a century later a future is being imagined where many bacterial infections cannot be treated with current medicines

• Commonly prescribed antibiotics are becoming less effective for many reasons, the main being:

  • Overuse of antibiotics and antibiotics being prescribed when not necessary

  • Large scale use of antibiotics in farming to prevent disease when livestock are kept in close quarters, even when animals are not sick

• These factors have led to a reduction in the effectiveness of antibiotics, and an increase in the incidence of antibiotic resistance

• These bacteria are commonly known as superbugs

• The most common example is a strain of Staphylococcus aureus that has developed resistance to a powerful antibiotic called methicillin as well as other antibiotics (eg. penicillin) and is now known as MRSA (Methicillin-resistant Staphylococcus aureus)

• Bacteria living where there is widespread use of many different antibiotics may have plasmids containing resistance genes for several different antibiotics, giving them multiple resistance and presenting a significant problem for doctors

• In addition, resistance may first appear in a non-pathogenic bacterium, but then be passed on to a pathogenic species by horizontal transmission

• There is a constant race to find new antibiotics as resistant strains are continuously evolving

Reducing antibiotic resistance & its impact

• Ways to prevent the incidence of antibiotic resistance increasing include:

  • Tighter controls in countries in which antibiotics are sold without a doctor’s prescription

  • Doctors avoiding the overuse of antibiotics, prescribing them only when needed (patients must only be given antibiotics when absolutely essential) – doctors should test the bacteria first to make sure that they prescribe the correct antibiotic

  • Antibiotics not being used in non-serious infections that the immune system will ‘clear up’ (patients must not keep unused antibiotics for self-medication of such non-serious infections in the future)

  • When prescribed a course of antibiotics, the patient finishing the entire course (even if they feel better after a few days) so that all the bacteria are killed, and none are left to mutate to become resistant strains

  • Antibiotics not being used for viral infections (antibiotics have no effect on viruses anyway, and this just provides an unnecessary chance for bacteria to develop resistance)

  • The use of ‘wide-spectrum’ antibiotics being reduced and instead those antibiotics that are highly specific to the infection (‘narrow-spectrum’ antibiotics) being used

  • The type of antibiotics prescribed being changed so that the same antibiotic is not always prescribed for the same infections and diseases (this reduces the chance of a resistant strain developing)

  • The use of antibiotics being reduced and more tightly controlled in industries such as agriculture – controls are now in place to limit their use in farming, where antibiotics are used to prevent, rather than cure, bacterial infections

• The spread of already-resistant strains can be limited by:

  • Ensuring good hygiene practices such as handwashing and the use of hand sanitisers (this has reduced the rates of resistant strains of bacteria, such as MRSA, in hospitals)

  • Isolating infected patients to prevent the spread of resistant strains, in particular in surgical wards where MRSA can infect surgical wounds

Consequences of pesticide resistance

• Pesticide resistance in insects is a problem for the security of future food supplies for human populations, especially those that already face food shortages

• Again, in a similar way to the use of antibiotics against bacteria, insecticides should be used sparingly or on rotation to avoid the evolution of resistance in pest insect populations

• Using a combination of pesticides can delay the emergence and spread of resistance in pest insect populations

• Farmers are also encouraged to use other forms of insect pest control, such as:

  • Biological control (introducing a natural parasite or predator of the pest insect)

  • Using crops that have been selectively bred or genetically modified to be pest-resistant