Fighting the resistance – Meet the scientists battling Antimicrobials to protect vulnerable Australians

18 November 2022

In a hospital, decisions need to happen quickly. Particularly for patients battling bacterial infections where every minute counts.

Doctors such as Morgyn Warner need to determine a course of antibiotics to help the patient fight the infection, often before blood results are returned.

So how is it possible to know which course of treatment is best without results?

Simply put, it's not.

By using data from Antimicrobial Resistance Groups such as AGAR (The Australian Group on Antimicrobial Resistance) and CARAlert (National Alert System for Critical Antimicrobial Resistance) we can determine which treatment is most likely to have a positive outcome.

World Antimicrobial Awareness Week was started in 2015 by the World Health Organization to help spread awareness of Antimicrobial Resistance.

Antimicrobial Resistance occurs when bacteria, viruses, fungi and parasites change over time and become resistant to antibiotics and other antimicrobial medicines.

This can have devastating effects, increasing the risk of disease spread, severe illness and death.

Groups such as AGAR – established in 1985, help monitor trends in resistance across the country and help doctors determine the best steps to take.

SA Pathology staff Dr Morgyn Warner, Kija Smith, Xiao Chen and Dr Kelly Papanaoum are part of the group contributing to the surveillance of antimicrobial resistance in South Australia at the Royal Adelaide Hospital, the Flinders Medical Centre and the Women’s and Children’s Hospital.

Frank Zhang, Xiao Chen, and Dr Kelly Papanaoum.	Malissa Amato, Samantha Pitson, Kija Smith, Dr Helena Torpy, Matthew Richens and Dr Morgyn Warner.

Blood culture isolates collected from patients are stored and sent to the AGAR group alongside susceptibility and demographic data, which includes factors such as the patient's gender, age, likely source of infection, length of hospital stay and clinical outcome. Our dedicated microbiology registrars devote many hours to providing this information.

There are members of the AGAR group in every state, which helps to build a picture of antibiotic resistance across the country.

Interestingly, the first option for treatment in one state, is not always the best in another.

The rates of antibiotic resistance for common antibiotics has shown a significant rise in the last decade.

• For instance, the proportion of E. coli resistant to the antibiotic ceftriaxone has risen from 8% to over 14% overall and even higher in some states.
• A decade ago, ciprofloxacin-resistance rates were consistently 1- 4% whereas in recent years the resistance rates have risen to 15-20%.

So what causes antimicrobial resistance? Kija Smith and Dr Morgyn Warner explain that it often is caused by one of two things - overuse of antibiotics causing our own bacteria to become resistant to antibiotics, or strains of bacteria that are already resistant to antibiotics entering into and spreading within the community.

“In some countries, you can go to a pharmacy and get any antibiotic you want, whereas here in Australia, we have a prescription system, so this helps with regulation and stewardship.

GPs have an important role in assessing patients and only providing antibiotic prescriptions when they are really needed. Bacteria can build up a resistance to an antibiotic if it is provided repeatedly so antibiotics should only be prescribed if necessary and always taken as directed.”

The other way people can become infected with antibiotic-resistant bacteria is a little more complicated, but it can be related to travel.

“Some bacteria carry antibiotic resistance genes on mobile elements called plasmids. Plasmids can easily be transferred from bacteria to bacteria, transferring their antimicrobial-resistant genes and protecting the bacteria from being killed by antibiotics.

So, some of the antimicrobial resistance we see in Australia is brought in after people travel overseas. On return, travellers, are sometimes colonized with bugs carrying these plasmids with resistance genes. These bacteria are not necessarily causing them any trouble, but they can pass those bacteria or the resistance genes on to somebody else who may develop a serious infection with an antibiotic-resistant bacteria.”

With COVID-19 border closures, a downturn in resistance trends in some bacteria has been noted, but the team is predicting an upturn in antibiotic-resistant organisms causing serious infections with the easing of travel restrictions internationally.

While many infections surveyed by the AGAR Group are relatively common, surveillance helps to keep Australia’s most vulnerable safe. Even common infections if not treated correctly, can become deadly.

Gram negative organisms such as antibiotic-resistant E. coli are amongst the greatest risks to human health. There are very few options for treatment of antibiotic-resistant bacteria and if treatment is available, it is often less effective and has more side effects. If extremely resistant organisms are identified, the SA Pathology antimicrobial team notifies the infection control service at SA Health and also sends out an alert nationally via the CARAlert notification system. Hospitalised patients colonised or infected with highly resistant bacteria need to be nursed with special infection control precautions on the ward to prevent spread of resistance within the hospital.

They include organisms that are highly resistant to all or most available antibiotic options.

“We’re lucky in Australia to have excellent oversight into what is happening in terms of antimicrobial resistance, thanks to programs such as AGAR. By understanding our local antibiotic resistance, we can optimise treatment for patients coming to hospital with sepsis.

With constant surveillance for highly resistant bacteria, we hope we will be able to keep them out of aged care centres and prevent them spreading in hospitals where some of our most vulnerable patients are treated. We’re trying to avoid resistant bacteria getting into those highest risk populations.”

Morgyn adds that she, Kija, Xiao and Kelly would also not be able to do this work without the help of microbiologists, junior doctors and scientists collecting the data.

Find out more about World Antimicrobial Awareness Week.