New increase in antimicrobial use in animals in Denmark

Antimicrobial usage in animals in Denmark continued to increase in 2013 -- mainly due to an increased use in pigs. However, antimicrobial use in pigs is still 12% lower than in 2009. In general, livestock received very little of the critically important antimicrobials, which are used to treat humans. These findings appear in the annual DANMAP report from Statens Serum Institut and the National Food Institute, Technical University of Denmark. DANMAP is the Danish integrated antimicrobial resistance monitoring and research programme. In 2013, the total use of antimicrobials in livestock and pets in Denmark was 4% higher than the previous year when measured in kilograms. The increased consumption is mainly attributed to a 6% increase in the consumption of antimicrobials in pig production, which accounts for about 84% of meat production in Denmark. But the consumption in poultry and pets has also increased.

Distributed by species, pigs account for around 78% of antimicrobial use in 2013, cattle 10%, aquaculture 3%, poultry 1%, fur animals 4%, and pets, horses and other companion animals the remaining 3%.

Increased use in pigs and poultry

Antimicrobial consumption in pigs measured in doses has increased in all three age groups: sows / piglets (9%), weaners (5%) and finishers (5%). This is primarily due to an increased consumption of pleuromutilins and tetracyclines, which are used for group medication. However, the consumption in pigs is still 12% lower than in 2009, when the highest consumption was recorded since Danish farmers stopped using antimicrobial growth promoters.

"It is crucial that we reverse the increase in consumption, if we are to tackle the problem of antimicrobial resistant bacteria," senior researcher Yvonne Agersø from the National Food Institute says.

In 2013, antimicrobial consumption in poultry increased by 57% compared to the year before. This is partly because of the wet winter, which led to more illness and -- as a result -- an increased consumption of tetracyclines in turkeys. An increased occurrence of diarrhea in broilers in 2013 can partly explain the increased consumption of penicillins, which are an effective treatment against diarrhea.

"Antimicrobial consumption in poultry is generally low compared to other species. It accounts for only 1% of the total use. For this reason, a few outbreaks of illness can cause significant fluctuations in the annual consumption data," Yvonne Agersø explains.

Continued low consumption of critically important antimicrobials

Consumption of critically important antimicrobials in animal production is still low. For a second consecutive year, the use of fluoroquinolones in pigs was very low in 2013 at less than 1 per mille of the total consumption in pigs. The use of 3 kilos of cephalosporins in pig production is also low. However, it does represent a significant increase compared to the year before when total consumption of cephalosporins was 1 kilo. There has been a significant drop in consumption in cattle.

"It remains important that Danish pigs and cattle are treated with critically important antimicrobials only when absolutely necessary to help ensure these agents continue to be effective when treating seriously ill people," Yvonne Agersø says.

In 2010 Danish pork producers introduced a voluntary ban on the use of cephalosporins where other effective treatment options are available. In August 2014, the Danish Agriculture & Food Council encouraged cattle farmers to only use cephalosporins where this is the only effective treatment option. Cephalosporins are not used in poultry production.

Companion animals and horses

Overall, the consumption of antimicrobials in the treatment of companion animals and horses increased in 2013 compared to the year before. This increase was not due to an increase in the use of critically important antimicrobials, as the consumption of both cephalosporins and fluoroquinolones in 2013 was lower than the year before. However, companion animals account for nearly 40% of the combined veterinary consumption of fluoroquinolones.

"While it is unfortunate that we continue to see an increase in the total use in companion animals, it is encouraging to see a drop in the use of antimicrobials that are critically important to humans. This suggests that the treatment guidelines put out by the Danish Veterinary Association in November 2012 has had some effect. The guidelines call for critically important antimicrobials to be avoided as much as possible," Yvonne Agersø says.

Facts about antimicrobial resistance

Treatment with antimicrobials is intended to kill pathogenic bacteria. Unfortunately, antimicrobials also cause the bacteria to protect themselves by developing resistance to the type of antimicrobials that are used to treat them. Resistant bacteria can be transmitted between humans, and bacteria can infect each other with resistance. However, resistant bacteria are poor at surviving if antimicrobials are not present. Therefore, it is important to have an overall focus on using as few antimicrobials as possible for the treatment of both animals and humans.

Bacteria know no borders, therefore antimicrobial resistance in one country can cause problems outside of its borders. As such the use of antimicrobials in both animals and humans is a global problem.

Not all antimicrobials are the same. Some are narrow spectrum and affect only individual groups of bacteria. They are used when you know which bacteria are causing the disease. Others are broad spectrum and affect numerous groups of bacteria at the same time. They can therefore be used to treat a disease before knowing which bacteria are the cause. However, they often also kill useful and harmless bacteria such as bacteria from the intestine, which may lead to the emergence of resistant bacteria.

Not all antimicrobials are equally important in the treatment of humans. WHO has declared a number of antimicrobials to be 'critically important', because they are the only or one of only a few antimicrobials, which can be used to treat serious or life-threatening infections in humans. These types include carbapenems, third and fourth generation cephalosporins, fluoroquinolones and macrolides.

Find the DANMAP report on DANMAP's website: http://www.danmap.org/

Source: Technical University of Denmark (DTU)