Page 3 - Foundation for Water Research Winter Newsletter 2020

the airport reaching our wastewater strength of evidence. The global increase
treatment plants (WWTPs), and our in living standards worldwide has led to
rivers and beaches within half a day. an increase in the consumption of meat,
Thanks to the practice of landspreading which has led to a situation whereby
sewage sludge (the solid waste that approximately 70% of all antimicrobials
accumulates in a WWTP), these exotic sold on earth are used to produce food
drug-resistant gut bacteria can also animals.
be found on our agricultural land as
an undesired component of the soil ENVIRONMENTAL CONTAMINATION
enhancer, which sludge represents to
farmers and society. Antibiotic use in humans and animals
inevitably results in their release of
ONE HEALTH between 30 to 90% of the mass of
the antibiotic in the urine and faeces.
Antimicrobials include all the drugs Antibiotic consumption selects for
that fight viruses (antivirals), bacteria antibiotic-resistant bacteria (ARB) in
(antibacterials), fungi (antifungals), the gut, which will be excreted from the
protists (antiprotozoals) and helminths human or animal along with the faeces.
(anthelmintics). If the challenge of These antibiotics and ARB find their way
antimicrobial resistance is not met with VETERINARY ANTIMICROBIAL USE into WWTPs (if human) or slurry lagoons
comprehensive action, then the limited and manure heaps (if animal). Nearly all
number of antimicrobials that we have Antibiotics are also widely used in food WWTPs discharge into a river, lake or
will leave humanity with few alternative animals, many of which have received coast, while slurry and manure is most
treatments for HIV (antiretroviral), growth-promoting antibiotics since the often spread on land as a fertiliser and
influenza virus (neuraminidase inhibitors) 1950s. Antibiotic use in animals is capable soil enhancer, called landspreading.
Aspergillus fumigatus (azole antifungals), of driving antibiotic resistance in human Erosion of land during heavy rainfall will
malaria (artemisinin antiprotozoal), bacterial infections, a phenomenon that further spread the drugs and bugs into
schistosomes (benzimidazole had been described in the literature the nearest water body, increasing the
anthelmintics). well over fifty years ago. The evidence risk of eutrophication from the nutrients
was sufficiently strong that in 1969 a and the spread of human and animal
HUMAN ANTIMICROBIAL USE UK-led committee produced the Swann pathogens, particularly if there is bathing
Report, which considered the human or recreational water ‘downstream’.
The global rise in antibiotic-resistant health risks from the widespread use of
bacterial infections is being met with a antibiotics in animal food production. CONSTRAINTS ON CONTAINING AMR
reduction in inappropriate antibiotic use in Unfortunately, the committee failed to
the UK. That said, recent evidence from make lasting policy advances despite the In the UK, human faeces are handled
Public Health England revealed that as through WWTPs, septic tanks and
much as 23% of all systemic antibiotic package sewage works. The latter two
prescriptions in English primary care typically treat one to ten homes in rural
had been prescribed inappropriately. locations. WWTPs are not designed for
Misprescribing of antibiotics persists because the removal of antibiotics or antibiotic-
doctors are often in a situation where resistant bacteria. Despite there being
they do not know the cause of a patient’s some reduction of antibiotics and ARB
illness. Among the most common reasons within a well-functioning WWTP (eg 10 to
for misprescribing is that the ailment is 100-fold decline), they will be chronically
caused by a virus, eg the common cold, not released into the river creating ‘hot spots’
a bacterium. Only antivirals will be of any of antimicrobials and ARB. The majority
use in controlling viral infection. Similarly, of low-income countries and many
antibiotics will only be applicable to bacterial middle-income countries have partial or
infections. However, doxycycline – a no treatment of human waste before it
common antibiotic – is routinely used for the enters the rivers.
prevention of malaria, a protist. Sewage treatment works

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