Resistant bacteria in intestinal tract linked to antibiotic usage

Published on
August 2, 2018

Researching the dung of more than 9000 pigs and chicken - scientists at Wageningen Bioveterinary Research and Utrecht University certainly aren’t deterred. Along with an international team they published the results of a study into antibiotic resistance in the prestigious journal Nature Microbiology. The level of antibiotic resistance in the intestinal tracts of pigs and broilers (meat chickens) turned out to be linked to antibiotic usage.

The international team visited 181 pig and 178 broiler farms in nine European Union countries, collecting more than 9000 animal dung samples.

More resistance with pigs

The study revealed that the quantity and type of resistance genes present in the intestinal tracts differ according to the type of animal and country. The animals - pigs and chickens - and the nine countries differ as far as resistance to antibiotics is concerned. This is a reflection of the difference in the degree of antibiotic usage per animal species and country. More resistance occurs in the intestinal tracts of pigs than in chickens, whereas a greater variety of resistance genes occur in chickens. The results of the study are of relevance not only to animals, but also to humans. Humans are after all exposed to resistance genes through food.

New approach

The researchers opted for a new approach to measuring resistance. They collected information via the DNA in the dung of the animals. This information codes for antimicrobial resistance in the overall bacterial community in the intestinal tract. This is called the resistome and comprises all the resistance genes present in the intestinal tract.

Combined effort

This publication is one of the outcomes of an international collaboration within the EU's EFFORT project: ‘Ecology from Farm to Fork Of microbial drug Resistance and Transmission’. The project aims to study the complex epidemiology and ecology of antimicrobial resistance and the interactions between bacteria in animals, the food chain and the environment. The project, which runs from 2013 up to 2018, is being coordinated by Jaap Wagenaar and Haitske Graveland of Utrecht University. The international team consists of 19 partners from 10 European countries (The Netherlands, Belgium, Germany, Denmark, Poland, Bulgaria, Switzerland, Italy, Spain and France). The Dutch institutes that played a major role in the recently published article are Utrecht University, faculty of Veterinary Science (Dick Heederik, Lidwien Smit, Heike Schmitt, Roosmarijn Luiken, Liese van Gompel, Alejandro Dorado and Jaap Wagenaar), and Wageningen Bioveterinary Research in Lelystad (Alex Bossers and Dik Mevius). The concluding symposium of the EFFORT project will take place in TivoliVredenburg in Utrecht in November.