Page 4 - Foundation for Water Research Winter Newsletter 2020

Increased population growth leads to a would be needed to ensure that the volume
demand for more homes. Housebuilding will of antibiotics entering the rivers from
very often proceed without consideration WWTPs was at a ‘low risk’ of selecting for
for the capacity of the sewage system to antibiotic resistance. The current aspiration
accommodate the substantial increase in by the NHS for reducing antibiotic use falls
the volume of water running off the new far short of this 80% mark.
roofs, pavements and roads. Hence, urban
sprawl has overstretched many sewage However, there are several different ways
networks leading to a sewage system that that such a reduction could be achieved,
is over capacity after only light rainfall. going beyond a reduction in NHS
Combined sewer overflows (CSOs) are prescribing, such as:
used as a safety release valve for the
sewage network, discharging untreated • point-of-care diagnostics that can
sewage and stormwater into the river or determine if an infection is bacterial and
coast, relieving the sewage system, and Storm runoff at Blantyre, Malawi to which antibiotic the bacterial infection is
reducing the risk of flooding homes and sensitive;
streets with sewage. The designation of COMBATTING ANTIMICROBIAL • greater range and uptake of all
rivers as ‘not suitable for swimming’ is RESISTANCE (AMR) vaccinations;
a tangible reflection of the frequency of • improved hygiene and sanitation (globally),
CSO discharges, as well as the real risk The UK’s revised five-year National AMR • improved infection prevention and control,
posed by agriculture and landspreading. Action Plan (2019–2024) stems from the particularly in the hospital setting;
Beaches are routinely closed in the UK as global movement, led by the World Health • educating doctors and patients of the
a result of CSO discharge – a direct result Organisation, to systematically tackle efficacy of prescribing antibiotics only
of the presence of the high abundance and antimicrobial resistance from a ‘One Health’ when it is needed, ie more reliance on
infectious nature of human pathogens that perspective (ie human, animal, agriculture the body’s immune system, in the first
will be present in such discharges. and environment). The UK AMR Action Plan instance;
recognises that ‘the presence of bacteria • reducing antibiotic course length where
In Wales, the only country within the and antimicrobials in sewage is a major possible;
UK where data on CSO activity and concern because of the potential release • improved welfare, hygiene and sanitation
duration is available, discharges from into service waters, groundwater, onto land in food animal production to reduce the
1,349 CSOs across Wales were reported and into the air’. It demands an improved need for antibiotics;
in 2018. A total of 87% of the CSOs in evidence base with respect to quantifying • introduction of novel technologies for
Wales (n=1,168) discharged at least once, and qualifying AMR in the environment, the treatment of sludge and manure to
for a combined discharge period of 39 with actions to include the identification lower the risk of spreading AMR from
years. Of those 39 equivalent years of and assessment of AMR sources, pathways landspreading (eg pyrolysis);
discharge, 22.5 years come from CSOs and exposure risks to people, animals • reducing the frequency of CSO discharges
that discharge over 100 times a year and ecosystems. However, there are no (to zero), by investing in the sewage
(n=136)! A litre of CSO sewage will have actions that speak specifically towards a network and more joined-up urban
at a minimum 10,000,000 bacteria and at reduction or elimination of antibiotics or planning;
least 1% of these will harbour antibiotic antibiotic-resistant bacteria from major • upgrading WWTPs to achieve substantial
resistance genes of clinical importance. known sources, such as WWTPs. A study removal of antibiotics, biocides, metals and
If the volume of CSO discharge was I published this past September revealed antibiotic-resistant bacteria.
monitored, it could then be estimated that an 80% reduction in macrolide and
how many clinically-relevant bacteria are fluoroquinolone antibiotics used in England The combined action of all these proposed
discharged, untreated, into Welsh rivers. measures will go a very long way to
This lack of data associated with CSO controlling the spread of antimicrobial
discharge and storm overflows (ie when resistance in humans, animals and the
the water reaching the WWTP exceeds the environment, which should lead to a
capacity of the WWTP) greatly limits our substantial reduction in antibiotic prescribing
ability to manage the environment and and drug-resistant infections. v
protect human health from pathogens,
particularly antibiotic-resistant bacteria. All images, except where stated, are copyright
Andrew Singer.
www.fwr.org 4 Issue 1 February 2020