INFECTION PREVENTION AND CONTROL
Are wastewater systems a nursery for microorganisms?
In the first in a series of three articles planned to run in HEJ in coming months, Dr Mike Weinbren, a consultant medical microbiologist at King’s Mill Hospital in Sutton-in-Ashfield in Nottinghamshire, and a Specialist Advisor, Microbiology, on England’s national New Hospital Programme, examines some of the major health risks to patients and staff from airborne and waterborne microorganisms transmitted via hospital wastewater systems.
Depending on how you look at it, the New Hospital Programme is either the perfect storm, or the perfect opportunity. England is set to build at least 40 new hospitals by 2030, a significant proportion of healthcare real estate. Expected to last for at least 60 years, these hospitals should still be operational in 2080. Such facilities will be operating over a period when the threat from antimicrobial resistance is likely to be at its fiercest. The highly influential review on antimicrobial resistance (AMR), ‘Tackling drug-resistant infections globally’, chaired by Lord Jim O’Neill, predicts a bleak future should there not be a major change in current practice.1
Predicting a potential
end of the antibiotic era by 2050, the estimated economic impact globally will be five hundred trillion dollars, and at least 10 million extra deaths year-on-year globally.
Undermining advances in medicine Antimicrobial resistance does not just affect the treatment of patients with infections, but also threatens to undermine most of the advances in medicine. Antibiotics are used to protect individuals during periods of immunosuppression due to cytotoxic drugs, as well as procedures requiring implants, i.e. prosthetic hip surgery. The past 15 years have seen an explosion in reports linking transmission of highly antibiotic-resistant organisms from wastewater systems to patients, in the most sophisticated healthcare economies around the world. The human gut contains more bacteria than there are people on the planet, most of which are Gram- negative organisms. It is among the latter group of organisms that the threat of the end of the antibiotic era emanates – and because these may be naturally carried in the human gut, they inevitably enter wastewater systems. The seriousness of the issue is exemplified by a small, but increasing number, of augmented care units globally moving to water-free patient care to terminate otherwise intractable outbreaks of highly resistant organisms originating from the wastewater system.
40 Health Estate Journal April 2023
Figure 1: How patient water jugs are traditionally filled, with placement in a sink, resulting in the base of the jug contacting the drain and associated organisms.
An intangible? For many, the consequences of antimicrobial resistance do not seem tangible. When a patient has a severe infection, irrespective of the source, the invading organism will gain access to the bloodstream. If a blood sample is collected and cultured the organism and its antibiotic sensitivity pattern may be determined. Patients presenting with sepsis are started on empirical antimicrobial therapy – a best guess before culture results are available. A multi-centre study from the USA found that 20% of patients with bloodstream infection were on ineffective antimicrobial therapy, as judged by laboratory testing.2 Patients on ineffective antimicrobial therapy had a higher mortality irrespective
of underlying condition or the presence of sepsis. As rates of antibiotic resistance increase, so will failures in empirical therapy. Patients are dying now as a consequence of antimicrobial resistance. This is not purely a scenario which happens when no effective antimicrobial agent is available. The consequences of AMR are tangible now.
Wastewater systems Although early civilisations including the Romans understood the requirements for separating clean water from human waste, the concepts of sanitation were lost in the mists of time until the advent of the industrial revolution. The large influx of rural populations into cities lacking both safe water and sanitation resulted
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