Occurrence of ESBL-producing Escherichia coli in healthy, living foodproducing animals in Europe : a systematic review

The objective of this paper is to review the recent scientific literature that focuses on the occurrence of extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-E) in healthy, living farm animals, namely chickens, pigs, and cattle, in European countries. Results The literature search retrieved 1,479 records, of which 157 articles were revised in full text. Finally, 17 of these satisfied the inclusion criteria. A great variety of methods to detect and quantify ESBL-E were described. Only a few studies have used the EUCAST guidelines. Major differences in study design and presenting results do not allow to report overall prevalence in the respective animal species, so “occurrence” is used when summarizing results. In broiler chicken, the occurrence of ESBL-E ranged between 80% and 96%. In pigs, the range was much wider, starting from 2.6% up to 84% in different sample and production types. In cattle, studies revealed an ESBL-E occurrence between 1% and 54%. Conclusion Although we found a high degree of heterogeneity in study designs and reports, it can be concluded that the occurrence of ESBL-E in food-producing animals in Europe is moderate to high, depending on the animal species. This review illustrates the extent of the problem and shows that appropriate measures need to be taken.