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Blog: The role of water in antimicrobial resistance

Kristen Houston

20 Oct 2022

One Health is a concept that recognises that the health of humans, animals and the environment are interconnected. In particular, this concept applies extremely well to the problem of antimicrobial resistance (AMR). Inspired by this week being National Water Week and the World Health Organisation’s One Health approach, we examine the connection between water and the rise of AMR.

The more bacteria become exposed to antibiotics, the more they have an opportunity to develop resistance and eventually turn into deadly superbugs. We often focus on antibiotic overuse, but what we wanted to highlight now is the pollution associated with this overuse in our waterways.

Did you know that traces of antibiotics and signs of antibiotic resistant bacteria can be found in just about any water source? This is a big problem. Antibiotics enter these water sources via contamination from aquaculture, landfill leachates[1], pharmaceutical manufacturing waste streams[2], agriculture runoff[3], sewage[4], and hospital wastewater. Further, human and animal waste can retain traces of antibiotics and antimicrobial resistant bacteria – and upon entering the water environment, these put pressure on other bacteria in the environment, causing them to also develop resistance or creating an imbalance in healthy microbiota of our waters. Countries with sophisticated water treatments have found it difficult to fully remove resistant pathogens, while countries with poor sewage infrastructure have an even harder time controlling these bugs.

It is estimated that swimmers in US ocean waters have a roughly 37 percent chance of encountering some form of Staph bacteria.[5] A 2009 study found the dangerous Methicillin-resistant Staphylococcus aureus (MRSA) at five out of ten public beaches along the San Francisco coast[6]. And a UK study found that surfers are three times more likely to have antibiotic resistant E. Coli in their gut.

In emerging nations, the burden is even greater due to “water poverty” or lack of quality drinking water. In a cruel paradox, diseases such as cholera, thyphoid and dysentery, that are caused by “bad” or pathogenic bacteria in unsanitary water (like Vibrio Cholerae, Salmonella typhi and Shigella) require treatment by more antibiotics again, further speeding up the process of resistance.[7] The World Health Organization estimates that if everyone had access to improved drinking water and sanitation, diarrheal illnesses that are treated with antibiotics would be reduced by 60%.[8]

The role of biofilms – impenetrable colonies of bacteria - in the development and transmission of infections is also key in the water environment. In water, microorganisms prefer to attach to surfaces in contact with water, forming multispecies communities embedded in a self-produced matrix, called biofilm[9]. The biofilm makes for an ideal ecosystem for antibiotic resistant bacteria to live, shelter from antimicrobials and share their resistance genes with other bacteria. Biofilms are commonly found in drinking water distribution systems and form the base matrix that barnacles and other fouling agents use to attach themselves to the hulls of ships and hydro turbines.[10] A recent study on healthcare-associated infections found that dangerous bacterial strains  (including K. pneumonia, S. aureus, E. coli and more) were “hiding” in difficult to detect and to remove  biofilms on water-associated devices such as faucets and shower heads.[11]  

While the full extent of antibiotic resistant pathogens in our water systems, is not fully understood, one thing is clear: human, animal and environmental health are interconnected and true AMR solutions must address issues in all three sectors to succeed.


[1] Anwar M.; Iqbal Q.; Saleem F. Improper disposal of unused antibiotics: an often overlooked driver of antimicrobial resistance. Expert review of anti-infective therapy 2020, 18 (8), 697–699. 10.1080/14787210.2020.1754797

[2] Larsson D. J. Pollution from drug manufacturing: review and perspectivesPhilosophical Transactions of the Royal Society B: Biological Sciences 2014, 369 (1656), 20130571. 10.1098/rstb.2013.0571

[3] Almakki A.; Jumas-Bilak E.; Marchandin H.; Licznar-Fajardo P. Antibiotic resistance in urban runoffSci. Total Environ. 2019, 667, 64–76. 10.1016/j.scitotenv.2019.02.183.

[4] Wang J.; Chu L.; Wojnárovits L.; Takács E. Occurrence and fate of antibiotics, antibiotic resistant genes (ARGs) and antibiotic resistant bacteria (ARB) in municipal wastewater treatment plant: an overviewScience of The Total Environment 2020, 744 (1–12), 140997. 10.1016/j.scitotenv.2020.140997.

[5] Sinigalliano, Christopher D et al. “Traditional and molecular analyses for fecal indicator bacteria in non-point source subtropical recreational marine waters.” Water research vol. 44,13 (2010): 3763-72. doi:10.1016/j.watres.2010.04.026


[7] Sack, R B et al. “Antimicrobial resistance in organisms causing diarrheal disease.” Clinical infectious diseases : an official publication of the Infectious Diseases Society of America vol. 24 Suppl 1 (1997): S102-5. doi:10.1093/clinids/24.supplement_1.s102


[9] Tsvetanova Z, Tsvetkova I, Najdenski H. Antimicrobial Resistance of Heterotrophic Bacteria in Drinking Water-Associated Biofilms. Water. 2022; 14(6):944.

[10] Papadatou, M.Robson, S. C.Dobretsov, S.Watts, J. E. M.Longyear, J., & Salta, M. (2021). Marine biofilms on different fouling control coating types reveal differences in microbial community composition and abundance. MicrobiologyOpen, 10, e1231.

[11] Hayward, Claire & Brown, Melissa & Whiley, Harriet. (2022). Hospital water as the source of healthcare-associated infection and antimicrobial-resistant organisms. Current Opinion in Infectious Diseases. 35. 339-345. 10.1097/qco.0000000000000842.

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