Massive replacement of multidrug-resistant pathogens between humans, domestic animals and wild animals

To re-evaluate the prevalence and transmission of multidrug-resistant pathogens
The exchange of pathogens between humans, domestic animals and wild animals has a decisive influence on the spread of antibiotic resistance, according to the results of an international study involving researchers from Freie Universität Berlin and the Robert Koch Institute (RKI). The researchers published their study results in the journal "PLoS Genetics".

The scientists found that "a globally occurring, multidrug-resistant ESBL-producing E. coli variant can be extensively transmitted between humans, domestic animals and wild animals," according to the RKI. This is what the analyzes of the pathogen family tree revealed. The exchange between the different species therefore has a significant influence on the spread of multidrug-resistant pathogens.

Researchers found that multirestial pathogens circulate between humans, wild and domestic animals. (Image: JackF / fotolia.com)

Pedigree analyzes indispensable for infection control
In addition to the researchers led by Alan McNally of Nottingham Trent University, Sebastian Günther and Katharina Schaufler from the Free University of Berlin and the President of the RKI, Lothar H. Wieler, participated in the study. Using a new bioinformatic method, the researchers were able to represent the pedigree of the pathogen in a previously unparalleled high resolution. Such "pedigree analyzes (phylogenetic analyzes) are indispensable for monitoring the development, spread and transmission of pathogens and antibiotic resistance and for improving the protection against infection," reports the RKI.

Pathogens circulate between humans, animals and pets
In the current study, the international research team analyzed the exchange of so-called ESBL-producing E. coli bacteria between humans, domestic animals and livestock. Scientists have been saying for some time that "the pathogens - and the hereditary traits that make resistance possible in the first place - circulate between humans, animals and the environment," says the RKI. An example of this is the multidrug-resistant ESBL-producing E. coli bacteria, which form special bacterial enzymes (so-called Extended Spectrum Beta-Lactamases, ESBL) and thus inactivate various antibiotics.

Analyzes of the nuclear genome as well as the accessory and regulatory genome
More than 200 isolates of a particular ESBL-producing E. coli variant (sequence type 131; ST131), which originated from different countries and hosts, were analyzed by the researchers. For their study, they combined for the first time the detailed analysis of the nuclear genome with the analysis of the accessory and regulatory genome, reports the RKI. The genome describes the entirety of all inheritable information of an organism and the nuclear genome occurs in all representatives of a species. In addition, however, there are additional genes that can vary, which in their entirety are referred to as the accessory genome. In addition, bacteria can "control their genome in a targeted manner" and "the areas responsible for this are called the regulatory genome," explains the RKI.

Look at the evolution of the pathogens
The combination of the analysis of all three genome regions enabled the scientists, according to their own statement, a view with unprecedented resolution in the evolution and distribution of these pathogens. In principle, "molecular surveillance, the complete investigation of pathogen genomes, and the analysis of development and dissemination, in infection control are becoming increasingly important," said the RKI. Multidrug-resistant Gram-negative bacteria (MRGN) would increasingly threaten medical progress in human and veterinary medicine. An essential prerequisite for molecular surveillance are powerful sequencers and the expertise of bioinformaticians. (Fp)