Multiresistant Gram-Negative Pathogens—A Zoonotic Problem.

Background: Extended-spectrum-β-lactamase-producing, carbapenemase-producing, and colistin-resistant Enterobacterales (ESBL-E, CPE, and Col-E) are multiresistant pathogens that are increasingly being encountered in both human and veterinary medicine. In this review, we discuss the frequency, sources, and significance of the zoonotic transmission of these pathogens between animals and human beings.

Methods: This review is based on pertinent publications retrieved by a selective literature search. Findings for Germany are presented in the global context.

Results: ESBL-E are common in Germany in both animals and human beings, with a 6-10% colonization rate in the general human population. A major source of ESBL-E is human-to-human transmission, partly through travel. Some colonizations are of zoonotic origin (i.e., brought about by contact with animals or animal-derived food products); in the Netherlands, more than 20% of cases are thought to be of this type. CPE infections, on the other hand, are rare in Germany in both animals and human beings. Their main source in human beings is nosocomial transmission. Col-E, which bear mcr resistance genes, have been described in Germany mainly in food-producing animals and their meat. No representative data are available on Col-E in human beings in Germany; in Europe, the prevalence of colonization is less than 2%, with long-distance travel as a risk factor. The relevance of animals as a source of Col-E for human beings is not yet entirely clear.

Conclusion: Livestock farming and animal contact affect human colonization with the multiresistant Gram-negative pathogens CPE, ESBL-E and Col-E to differing extents. Improved prevention will require the joint efforts of human and veterinary medicine.