Modelling of antibiotic resistance in aquatic systems: a useful tool to protect human and ecosystem health

Antibiotic resistance in aquatic systems puts the health of people and animals at risk from diseases caused by antibiotic-resistant bacteria. Scientists at the International Water Management Institute (IWMI) are working with research partners on modelling of water quality to understand how antibiotic-resistant bacteria and antibiotic resistance genes are transmitted in water systems. Their findings will guide interventions aimed at reducing water pollution and the spread of antibiotic resistance. In this post, IWMI researchers Mahesh Jampani and Javier Mateo-Sagasta discuss how water quality modelling can help tackle the threat of antibiotic resistance.

Before the invention of antibiotics, even a minor bacterial infection was deadly.

Over the last century, antibiotics have saved countless lives by treating microbial infections.

However, common antibiotics have been rendered ineffective in recent decades because of their overuse and misuse, leading to the threat of antibiotic resistance.

A recent study on the global burden of antimicrobial resistance estimated that antibiotic-resistant infections caused 1.27 million deaths in 2019, and this number could rise to an estimated 10 million by 2050.

The World Bank has warned that if antimicrobial resistance is left unaddressed, the compounding economic impact will be more than 1 trillion United States dollars annually after 2030.

The recent COVID-19 pandemic might have worsened the problem, triggering intense antibiotic over-consumption because of several misconceptions.

It is commonly assumed that antibiotic-resistant bacteria (‘superbugs’) are only associated with the overuse and misuse of antibiotics in animal farms, households or hospitals, but the environment, especially water resources, play a role in spreading antibiotic resistance.

Scientists at the International Water Management Institute (IWMI) are collaborating with local and international partners, through the CGIAR Initiative on One Health, to conduct research and provide evidence-based solutions to address water-related challenges and contribute to evidence-based solutions in the context of One Health.

The role of water

Antibiotics, antibiotic-resistant bacteria and antibiotic resistance genes from various sources and pathways enter aquatic environments, where they can spread resistance to other susceptible bacteria.

Thus, the water systems we regularly depend on for drinking, irrigation, fishing and recreational activities can become potential reservoirs and conveyors for these harmful bacteria.

The emergence of antibiotic resistance in water systems has become a major global concern that must be urgently addressed to ensure the safety and sustainability of our water resources.

A research study by IWMI’s Mahesh Jampani as lead author and published in the Journal of Hazardous Materials identified several factors, such as selection pressure and horizontal gene transfer, that play a key role in the development of antibiotic resistance in water systems.

High concentrations of antibiotics in polluted environmental water and sediments are likely to be driving the selection of antibiotic-resistant bacteria, posing a significant threat to human and ecosystem health given the central role of water in our daily lives.

Understanding the fate and transport of antibiotic-resistant bacteria and antibiotic resistance genes can help scientists predict where these bacteria might end up and their likely effect on public health and the environment.

Modelling antibiotic resistance 

Models represent real-world systems and thus can help us to better understand complex problems by identifying cause-and-effect relationships, enabling predictions of future scenarios and determining strategies to manage the problem.

Water quality models are useful because they can simulate the movement of pollutants and help us to understand their impact on human health and ecosystems.

These models can also be used to determine the effectiveness and cost of remedial actions.

To effectively tackle antibiotic resistance in water systems, we need to understand its complex dynamics in the environment.

Water quality modelling is a useful tool to do this, as it can simulate different scenarios and evaluate the effectiveness of various measures aimed at reducing the spread of antibiotic-resistant bacteria and antibiotic resistance genes.

Water quality models can track the transmission routes and assess the fate and transport of antibiotic-resistant bacteria and antibiotic resistance genes, predicting their movement influenced by factors like water flows, hydrological processes, resistance mechanisms and microbial interactions.

With a robust modelling framework, comprehensive and more accurate models can be developed to guide policy decisions and management strategies to reduce the spread of antibiotic resistance in water systems.

Dealing with model complexities

Microbial water quality models that can evaluate the fate and transport of antibiotic-resistant bacteria and antibiotic resistance genes are being developed to better understand how these bacteria and genes behave in water systems.

While some processes related to the spread and development of waterborne antibiotic resistance are well-known, others are not yet understood; even so, accurate and robust models can still be built by making reasonable assumptions.

Empirical models can be used when there is a lack of enough data to build process-based models, which are more reliable.

In the near future, scientists will be able to predict potential antibiotic resistance hotspots by understanding how and where the resistant bacteria spread.

This predictive power will be useful for managing ecosystems, preventing disease outbreaks and framing effective response strategies.

Developing robust water quality models that can simulate the transmission of antibiotic-resistant bacteria and antibiotic resistance genes in water systems will require significant investments.

Reducing health risks

The scenarios developed using water quality models can help to identify effective management strategies to reduce risks, such treatment of wastewater and regulating the use of antibiotics for animal and human health.

The battle against antibiotic resistance is multi-faceted and not just a hospital problem; it is an environmental one and thus needs to be tackled in the context of One Health.

Through water quality modelling of antibiotic-resistant bacteria and antibiotic resistance genes, researchers are equipped with improved understanding on what is needed to protect water ecosystems and human health.

Photo: Collecting water for household use near Chilhar, Tharparkar, Sind, Pakistan (IWMI/Muhammad Usman Ghani)