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Drinking water plumbing a hotspot for superbugs

A growing threat of antimicrobial resistant (AMR) pathogens poses a critical public health threat—and drinking water plumbing systems serve as significant but overlooked reservoirs of these problematic microbes.

Despite international efforts to combat AMR, surveillance has primarily focused on clinical cases, while environmental reservoirs—such as drinking water plumbing systems—remain poorly understood.

A recent study by researchers from Flinders University and other leading institutions revealed alarming findings about bacterial persistence in Australian drinking water plumbing, and identified significant transmission risks in both hospital and residential environments.

"The presence of these antimicrobial-resistant bacteria in residential and hospital plumbing systems highlights a pressing public health concern that requires immediate attention," says Flinders University's Professor Harriet Whiley.

Published in the Journal of Hospital Infection, the assessed the prevalence of key AMR threats—being methicillin-resistant Staphylococcus aureus (MRSA), plus carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter baumannii—in hospital and residential drinking water and biofilm samples across Australia.

Key findings showed:

• 73% of residential water and biofilm samples tested positive for at least one AMR pathogen, compared to 38% of hospital samples.
• 45% of residential drinking water plumbing fixtures had at least two of the targeted AMR pathogens, highlighting the risks in home environments.
• Drain biofilms were identified as a major reservoir for AMR bacteria, contributing to their persistence even after disinfection efforts.
• Carbapenem resistance genes were found in biofilm samples that tested negative for P. aeruginosa, suggesting biofilms may act as long-term reservoirs for AMR genes, which will allow resistance to spread even after the original bacteria have died.
• MRSA, typically associated with dry, high-touch surfaces such as bed rails and doorknobs, was detected in both water and biofilm samples. This indicates that AMR pathogens that are not traditionally considered waterborne may thrive in plumbing systems.

Antimicrobial resistance is among the most pressing 21st century global health challenges. The World Health Organization (WHO) warns that by 2050, AMR infections could cause 10 million deaths a year, and would therefore surpass cancer as the leading cause of death worldwide.

Resistant infections already lead to prolonged hospital stays, higher medical costs and an increasing reliance on last-resort antibiotics, which are becoming less effective.

"Our research underscores the urgent need for enhanced surveillance and targeted interventions to mitigate the risks posed by AMR pathogens in drinking water systems, especially in home health care settings," said lead researcher Dr. Claire Hayward.

This study calls for improved strategies to manage AMR risks in water infrastructure, particularly in environments housing vulnerable populations, such as hospitals and aged care facilities.

Strengthening water system hygiene, routine monitoring, and innovative biofilm control methods could play a crucial role in addressing this growing threat.