Antimicrobial resistance explained

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

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 (AMR) 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.

Learn more about bacterial genetic expression to survive stress in the articles Bacterial DNA – the role of plasmids and Bacterial transformation.

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 resistance

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 articles Global report on antimicrobial resistance and Is the post-antibiotic era now here? provide additional information on these topics.

The hunt for new antimicrobial medicines

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 Siouxsie 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.

Spreading awareness and improving community health literacy

In 2017, South Wellington Intermediate School teacher Matt Boucher was on a Royal Society Te Apārangi Science Teaching Leadership Programme at the University of Otago’s Wellington campus (which is associated with Wellington Regional Hospital).

Matt developed a keen interest in microbiology and attended a series of meetings with the infectious disease team. Matt and a couple of the antimicrobial pharmacists on the team, Chris Little and Emma Henderson, could see the potential to engage young people in some authentic science learning around a problem that affects them and their wider community – the pressing issue of antimicrobial resistance.

Together, they designed a local poster competition to enable children to create their own messages about antimicrobial resistance and the basic steps needed to stop the spread of disease such as hand washing and wound care.

In 2018, the competition was picked up by the Health Quality & Safety Commission, Ministry of Health and ACC as part of the Commission’s annual Patient Safety Week. The competition was promoted through schools, media releases and social media activity, and more than 250 entries were received from across the country.

There were several prizes up for grabs, including 10 $50 movie vouchers for the highly commended posters and a special edition scooter for each of the regional winners. The overall winner received a trip to the laboratory at Wellington Regional Hospital to experience science in action!

2018 competition award winners

The overall winner of the 2018 poster competition was Libby from Cust School. Regional winners were Pippa from South Wellington Intermediate School, Ruby-Jean and Astra from Belmont School and Melody from Te Kāpehu Whetū.