Antibiotics measures: A global overview

Besides the controversial legislation work going on in the European Union, there are major changes going ahead in the United States on the way antibiotics are used in food-producing animals and the global community via the G20 and United Nations are pushing ahead to improve antibiotic monitoring and usage at a farm level.

Global strategy

The G20 have endorsed the work that is required regarding anti-microbial resistance (AMR) in their statement following the Hangzhou meeting in China:

“46. Antimicrobial resistance (AMR) poses a serious threat to public health, growth and global economic stability. We affirm the need to explore in an inclusive manner to fight antimicrobial resistance by developing evidence-based ways to prevent and mitigate resistance, and unlock research and development into new and existing antimicrobials from a G20 value-added perspective, and call on the WHO, FAO, OIE and OECD to collectively report back in 2017 on options to address this including the economic aspects.

“In this context, we will promote prudent use of antibiotics and take into consideration huge challenges of affordability and access of antimicrobials and their impact on public health. We strongly support the work of the WHO, FAO and the OIE and look forward to a successful high-level meeting on AMR during the UN General Assembly. We look forward to the discussion under the upcoming presidency for dealing with these issues.”

More antibiotic resistance

AMR is also on the agenda at the United Nations General Assembly meeting this month (21st September), with the UK, surprisingly, driving much of the agenda and backing it with the £265 million (€306 million) Fleming Fund to be spent over 5 years to improve the surveillance situation globally and especially in middle and low income countries.

Many of these countries do not have basic AMR monitoring or legislation to introduce it or control antimicrobial use or quality.

The market for counterfeit products is also a major issue. It will be interesting to see how much the UN can commit to this but they see AMR as critically important, similar to tuberculosis in man, HIV infections and Ebola virus control, where they have developed an infrastructure to monitor and control such infections in many countries. A number of countries, including China, are putting together National Action Plans to improve their local situation.

Findings on antibiotics in South East Asia

I was fortunate to attend a meeting at Chulalongkorn University, Bangkok, Thailand in April this year on AMR in animals, where they presented their research findings for SE Asia and there were also excellent papers from FAO and OIE on their work in the region.

I was presenting a paper on the attribution rate of resistance from pigs and chickens to man based on EU data collected by EFSA and ECDC. So this surveillance work is already starting to roll out.

Antimicrobial strategy in United States

In the USA, they are preparing for the forthcoming changes to the use of antimicrobials considered/listed as important in man and their use in animals. This will start from 1st January 2017, and Canada is expected to follow also. The main requirements are:

• These important antibiotics cannot be used for growth promotion.
• They will only be used to keep animals healthy.
• They can be used for prevention, control (EU metaphylaxis) and therapy.
• Their use should be supervised by a veterinarian and in-feed use will come under a veterinary directive.

Injectables do not appear to be included at this stage, but usually they are comparatively small use in pigs in volume terms but do contain the critical use antibiotics such as the cephalosporins and fluoroquinolones.

So when all the changes come into place the world will be divided into different regions how antibiotics will be used (see Table 1).

Control in the hands of a veterinarian

I may be biased, as I am a veterinarian, but I think that it is good that medicinal control comes into the hands of the veterinarian, as this can then be linked to health and disease control programmes on the farm. The banning of growth promotion is probably a good thing to reduce overall use, especially, as it does not involve a complete ban of the drug in the US.

I remember an exceptional growth promoter in pigs in the UK, halquinol (Quixalud), moved from a growth performance (GP) to vet control status and sales fell 80% but it was still available for controlling E. coli. When Denmark banned growth promoters back in the late 1990s, suddenly, it caused some major problems and almost a trebling of the use of therapeutic drugs.

Growth promotion or prevention?

In the USA, they have been clever and moved them from growth promotion to prevention of disease over a 3-year period. This is important as many people did not know or understand that the GPs also had a preventive effect against some diseases – e.g. Clostridium perfringens, the cause of necrotic enteritis in chickens was one example – and on banning some of the GPs like avoparcin and virginiamycin in 1999 there were major problems in the UK and amoxicillin (a major therapeutic drug) sales grew dramatically fourfold to treat necrotic enteritis.

By the time 2006 came along when the main GP ban in the EU took place most farmers were ready for the change and there were comparatively few problems.

Controversial legislation in the EU

In the EU they are proceeding with their controversial legislation and working through the amendments. It is hoped that the final, more sensible documents will be agreed by the EU Council, Commission and Parliament in 2017 and implementation by member states by 2019.

One recent strange development in the EU has been the proposed reduction in the use of copper from 170 ppm to a proposed 25 ppm in feed, for nutritional purposes only by EFSA. The feed industry is up in arms as these already low levels were helpful in controlling post-weaning diarrhoea in piglets and improved growth.

Increase in copper resistance?

One reason put forward was an increase in copper resistance seen by Salmonella monophasic bacteria. The resistance went up from 2.554 µg/ml to 3.384 and 3.862 µg/ml and they say this is a significant change (Petrovska and others, 2016). To me it is not even one dilution difference so I cannot see how it has effectively changed.

Copper levels in the gut at 170 ppm in feed are approximately 85 µg/ml in the small intestine and 284µg/ml in the large intestine and I would not call it resistant at all. EFSA needs to clarify this. The timing is also not great when all the antimicrobial changes are taking place either.

Allowing pig farmers to adjust

Globally there are potentially some major moves on the horizon to improve AMR surveillance, which can only be beneficial for animal health and farmers. The removal of the use of antibiotics as growth promoters, if introduced cautiously allowing farmers to adjust is usually OK, especially, if they can access them as preventive medication like in the USA. This is a very sensible move.

I do believe in veterinary control as most of the time we are dealing with disease control and if used responsibly, as part of farm health plans, this can also be very beneficial for producers. The rest of the world are in a variety of stages of development but antibiotic usage and AMR surveillance has got to be helpful for them long term. Whether we have any new antibiotics for veterinary/animal use, who knows, but human use will be the key priority.