Globally, the overuse and misuse of drugs – especially antibiotics – in the food chain and in the pollution from livestock farming (spills of manure and other waste into soil and waterways), is a major contributor to the rapid rise of superbugs.
With antibiotic use also prevalent in the South African agricultural and farming sector, it’s a very real problem for this country as well, notes MedicalBrief, but one which the government is focusing on reducing, with steps already being taken to tackle the issue.
A new global report says that in 2019, drug-resistant infections were directly responsible for almost 1.3m deaths, and contribute, says the World Health Organisation (WHO), to more than 5m deaths per year.
The report, from the UN Environment Programme (Unep), also estimates that up to 10m people a year could die by 2050 because of antimicrobial resistance (AMR) – that’s the same as the number of people who died from cancer in 2020.
Limiting the spread of antimicrobial resistance is critical to preserving our ability to reduce disease, food-safety and food-security risks, and protect the environment, reports Maverick Citizen.
The WHO has been sounding the alarm on AMR since the early 2000s as one of the world’s top 10 global health problems, releasing a “global action plan” on AMR in 2015.
Now, the new Unep report takes an updated global overview of the issue: Bracing for Superbugs amplifies the WHO’s frequent warnings that AMR poses an urgent and critical threat to animal and plant health, food security and economic development.
Pollution from biological and chemical sources fuels antimicrobial resistance’s development, transmission and spread, the report says, with three sectors in particular driving it: agriculture and food, healthcare, and manufacturing of pharmaceutical and other chemicals.
“What drives resistance is use, overuse or inappropriate use,” says Professor Moritz van Vuuren, vice-chair of the Ministerial Advisory Committee on Antimicrobial Resistance (MAC-AMR), and Emeritus Professor of veterinary microbiology at the University of Pretoria.
“The moment you use an antibiotic, you create the possibility for resistance to develop. So, the more inappropriately you use it, the more you drive resistance.
“There’s always been concern about the quantity of antibiotics used in feed and water of animals …
“But it’s not the main cause of resistance in human pathogens. Those multidrug-resistance bacteria are the result of overuse and inappropriate use of antibiotics in humans.”
University of Cape Town’s Professor Marc Mendelson, MAC-AMR chair and head of infectious diseases and HIV medicine at Groote Schuur Hospital, has said that about one-third to one half of antibiotics used in humans are unnecessary, often for viral infections like flu or bronchitis.
“Antibiotics only work against bacterial infections, not viruses or non-specific symptoms,” he said. “All they are doing when misused is to increase resistance and cause unwanted side-effects.”
Why antibiotics in animal farming?
This is amplified in animal use, given the massive scale of it. Nearly three-quarters of all antibiotics used worldwide are used on animals grown for food, The Guardian reported in 2019, and include antibiotics “of last resort” for human use.
In many countries, there is little regulation to curb this, but scientists “have struggled to estimate the size of the problem due to a lack of data in most of the developing world”, Guardian environment editor Fiona Harvey wrote.
Why are antibiotics considered necessary in animal farming? It comes down to the high-intensity methods used in commercial farming.
Under pressure for rapid growth and high yields, farmers often keep animals in overcrowded, unhygienic conditions where bacteria flourish, and animals’ immune systems are weakened by stress. Females are often not given enough time to recover between pregnancies, placing further stress on their immunity. And when animals get sick, just like humans, they need treatment.
Mendelson highlights the commercial imperative, though: “The animal protein production industry is often about fine margins, and getting animals to market in the shortest time at a decent size and in optimal health, is a constant challenge,” he wrote in an opinion piece in 2022.
Antibiotics can be used in animal farming in three ways, Van Vuuren said: To treat an individual animal, to prevent disease spreading within a group, or to prevent disease in general, even with no apparent infections.
This used to mean antibiotics were used liberally and routinely in animal farming to prevent disease, not just to treat sick animals. But scientists are clear about prohibiting antibiotic use as growth promoters and for disease prevention.
Van Vuuren says South Africa is moving away from that approach.
“There have been huge changes and improvements in South Africa,” he told Maverick Citizen. “We’re not nearly where we were 10 years ago when antibiotics were used liberally in the feed of production animals.
Preventative use is what we’re trying to get away from globally, and very much so in SA,” he says, as well as using antibiotics to promote animal growth.
This is despite government regulations still not prohibiting antibiotics for growth promotion. (The relevant legislation, from 1947, allows them to be sold over the counter for use in animal food and water, with no explicit limits on using them for growth promotion.)
However, South Africa’s response to AMR overall – not just relating to animals – is now guided by the South Africa Antimicrobial Resistance Strategy Framework of 2018-2024.
About three years ago, Van Vuuren said, the South African Animal Health Association decided to change the package inserts of their antibiotics “to exclude growth promotion and prophylactic use”.
This was a voluntary act, albeit under pressure from various industry-related sources.
“An antibiotic for use in feed and water will never again be registered in this country with a claim for prophylaxis or growth promotion,” Van Vuuren said.
“You can never ‘ban’ the use of antibiotics in animals, because they need it just like humans do, for therapy. But, yes, there will eventually be regulations prohibiting growth promoters … but it’s already being voluntarily phased out by the industry.”
The next regulatory step, Van Vuuren says, is to place all antibiotic use under veterinary oversight, meaning only vets can prescribe, dispense or administer antibiotics.
Those discussions are ongoing “as we speak”, said Van Vuuren, who was on his way to a South African Health Products Regulatory Authority (Sahpra) meeting on this issue the next day.
But what about the antibiotics used for animal treatment – are we being exposed to those in our dairy products, meat, chicken and fish? Officially, “no”.
Antibiotics used for animals have what are known as “withdrawal periods”, to which farmers have to adhere (mandated by the same legislation authorising registration of antibiotics).
This means the antibiotics given to an animal take a certain time to get metabolised and work their way out of the system through natural biological processes. Farmers have to wait until this happens before slaughter or milking.
“The residues are essentially non-existent,” Van Vuuren says, describing routine testing procedures performed by commercial laboratories. They are contracted by major dairies, for example, to test every bulk batch of milk delivered to a depot. “It’s an absolutely routine procedure,” he says.
“Whenever milk is collected on a farm, a sample is taken in a specific container,” Dr Chris van Dijk, a bovine veterinary specialist, told Maverick Citizen.
Then, when the tankers transporting milk in 30 000-litre tankers (with compartments) are delivered to the depot, samples are taken from each compartment, before the milk is pumped out. If analysis of the samples from each compartment shows antibiotic residue, the entire batch is discarded – a huge financial loss for the farmer and a clear incentive to toe the line.
“These tests are highly sensitive and qualitative,” says Van Dijk, naming several antibiotics tested for, “and will demonstrate a positive sample if it is above the defined MRL [maximum residue level as defined by law] for the specific antibiotic”. (The milk is tested at the same time for E. Coli, cell count as an indicator of milk quality, a bacterial cattle disease called brucellosis, as well as for water, protein and fat content.)
Why did antibiotic use in animal farming begin?
The use of antibiotics to promote growth in commercial food animals was approved in the US in the early 1950s (around the time that intensive animal farming was revving up) as well as to minimise disease.
The European Union banned the use of antibiotics and all related drugs in animal feed for growth-promotion purposes in 2007, and the US instituted a similar ban in 2017, antibiotics being permitted only for disease treatment or prevention purposes under vet supervision.
China outlawed antibiotic growth promoters in July 2020, after a study showed possible transmission of resistant Campylobacter bacteria from pigs to humans, to improve the effectiveness of therapeutic antibiotics
Still, China and the US remain the heaviest users of antibiotics in animal farming, accounting for a large chunk of the three-quarters of total antibiotic use, which is fuelled by increasing meat consumption.
In many developing countries, however, there is no legislation on antibiotics (or antimicrobials, more broadly) in livestock use. This means better-regulated countries are not insulated from the risk of antibiotic or antimicrobial resistance.
AMR can spread quickly, and far – one example reported in 2019 in the journal Environment International proved that genes associated with an antibiotic-resistant superbug first found in a patient in India in 2007-08, then in surface waters in Delhi in 2010, were later found in the soil of Svalbard in the
Norwegian archipelago, in the Arctic Circle.
Four global organisations are spearheading the so-called OneHealth approach: The Food and Agriculture Organisation of the UN, the WHO, the World Organisation for Animal Health and the UN Environment Programme, recognising the interdependence of human, animal and plant health and environment, and proposing a range of coordinated actions.
Van Vuuren said South Africa is at the vanguard:
“We are on the front foot in terms of embracing OneHealth – people from the medical, veterinary and environmental ‘compartments’ are working together impressively,” he said.
“We’ve made great progress with antibiotic stewardship.”
But, he cautions, “We don’t want to create the impression that AMR is not important – it is still one of the world’s biggest risks to mankind [along with climate change and overpopulation].
“There was a perception about a decade ago that AMR was 99% due to antibiotic use in animals – but antibiotic use in animal farming is not the most important element. It is a contributor and should be addressed, but both human and animal use contributes equally to driving resistance.
“Whenever you use antibiotics it contributes to AMR. So, the new mantra is, ‘how do we diminish the need for AB in animal husbandry?’
“I don’t want people to think there is no control or effort to address this. The one thing happening is that antibiotic stewardship is being managed by a great group of professionals who ‘know their onions’, and are doing this according to the book.”
antimicrobial_Reportsouth-africa-antimicrobial-resistance-national-action-plan-2018---2024
See more from MedicalBrief archives:
Urgent need for more funds to fight AMR drug resistance
SA health experts call for ban on use of colistin in agriculture
UK farmers to reduce animal antibiotics
Fresh strategies needed to rein in excessive antibiotic use