Microbes – friend or foe? Some microbes are essential to life, while others cause sickness in plants and animals, including humans. For decades, we have kept most infectious diseases under control, thanks to vaccines and antibiotic and antiviral medicines. However, it’s estimated that growing antimicrobial resistance has the potential to kill 10 million people globally per year by 2050.
It is a zombie apocalypse arising, it is a crazy thing and we really do need to start thinking about it.Dr Siouxsie Wiles
The antibiotic age
Modern antibiotic medicines like penicillin, streptomycin and tetracycline came into use in the middle of the 20th century. Half of the antibiotic medicines we commonly use today were discovered between 1950 and 1960. They enabled doctors to treat serious – and sometimes fatal – bacterial infections like strep throat and pneumonia. Prior to antibiotics, even simple cuts and grazes could be dangerous. Human life expectancy increased by 8 years during the 1944–1972 period – thanks in part to antibiotics.
Antiviral medicines were first developed in the 1960s. In the beginning, it was a slow process to create them. Viruses are not living, so a virus needs a host cell to replicate itself. Medicines need to try to target the virus without harming the host cell. Advances in genetic sequencing have helped researchers to identify and treat viral diseases. Vaccines have been developed to help us acquire immunity to viruses like measles, hepatitis and influenza. Vaccinations are the main defence against most viruses. However, some viruses mutate at a fast rate – faster than we can alter and produce vaccines to combat them.
Antibiotic resistance is not a new concept. In 1945, Alexander Fleming (who discovered penicillin) warned that too small doses would educate microbes to resist penicillin rather than clear up the infection and that a host of “penicillin-fast organisms” could be passed to other individuals until they reach someone who penicillin cannot save.
Transferable antibiotic resistance was first discovered in Japan in the 1950s. Researchers also noted that resistance began to develop 2 or 3 years after a new antibiotic treatment was introduced.
Antimicrobial resistance explained
Any use of antibiotics automatically creates resistance. Antibiotics are designed to either kill or inhibit the growth of bacteria. Bacteria react to this threat – as to any threat from their environment – by evolving. Random mutations occur, and some may be resistant to the antibiotic. As bacteria continue to be exposed to the antibiotic, the resistant bacteria become more common. Meanwhile, successive mutations allow the bacteria to become resistant to ever-higher concentrations of the antibiotic medicine. Bacteria can also gain resistance via gene transfer from other bacteria, even between bacteria of different species.
Bacteria are not alone in developing resistance. Other microbes, including viruses, fungi and parasites, also mutate. Influenza is a viral infection and spreads rapidly. Vaccination is the preferred means for preventing influenza, but antiviral medications such as Tamiflu are used during flu epidemics. Research shows high rates of emerging resistance to Tamiflu, even after a single course of treatment. Resistance is also occurring in antiparasitic medicines, like those used to treat malaria.
Reasons for antimicrobial existence
There are numerous reasons for the spread of antimicrobial resistance:
- Incorrect and excessive use of antibiotics in humans and animals.
- Globalisation allows resistant microbes to move from one part of the world to another via travel and trade.
- Consumer products containing antimicrobial agents introduce stressors – similar to antibiotics – accelerating the development and spread of resistance in bacteria and fungi.
- Antimicrobial medicines and agents used for humans and animals do not break down but are released into the environment via commercial, industrial or agricultural wastewater.
There are a number of common-sense approaches we can take to help slow the spread of antimicrobial resistance:
- Practising good hygiene and using soap and water rather than antimicrobial cleaning products.
- Correct use of prescription antibiotics.
- Rethinking medical tourism as a cheaper means of seeking medical treatment.
- Staying up to date with vaccinations.
The hunt for new antimicrobial medicines
Nature of science
The field of science offers many ongoing challenges – the need for new thinking and innovation does not change. There will always be opportunities to further our understanding, make new discoveries and create new technologies in response to old and new challenges.
The growing need for new drugs to replace those that are no longer effective encourages researchers to look for novel solutions:
- The article Antibacterial mushrooms highlights research regarding the antibacterial and antioxidant activities of native New Zealand mushrooms.
- In Bioluminescence and superbugs, Dr Siouxie Wiles explains how she uses bioluminescent bacteria as a tool for assessing how well antibiotics and vaccines work against superbugs.
- How honey heals wounds and From bees to bandages explain the antibacterial properties of honey.
- Bioactive milk proteins attack acne explains how bioactive proteins act as a powerful antimicrobial agent.
- New Zealand company Mende Biotech uses old tōtara fence posts to create Totarol™ – an antibacterial and antimicrobial compound.
Royal Society Te Apārangi has produced a series of articles and videos about antimicrobial resistance, including the te reo resource He uaua ake te rongoā i ngā whakapokenga ātete rongoā.
Learn more about Totarol™ – the tōtara-based antibacterial plant extract .
Listen to Dr Siouxie Wiles as she discusses the rise of resistant superbugs in this Radio New Zealand interview.
Watch antibiotic resistance evolve in this video from Harvard Medical School.
Three of the videos used in this article were produced by the Royal Society Te Apārangi. For more information about antimicrobial resistance, visit their Expert Advice webpage.