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Imprint
Characterisation of colistin resistant Salmonella strains, screening for mcr genes and research on novel colistin resistance determinants.
Project
Project code: BfR-BIOS-08-1322-715
Contract period: 01.01.2019
- 31.12.2019
Purpose of research: Experimental development
The polymyxin antibiotic colistin belongs to the last-resort antibiotics. In 2015 Liu et al. first described a mobile plasmid-located and therefore transferrable colistin resistance gene (mcr-1). Since then colistin resistance in bacteria isolated from farm animals, food and patients came back into focus of scientists from public health, animal health and food safety sectors. In the years 2016 to 2018, seven additional mcr genes (mcr-2 to 8) were identified. A PCR screening of approximately 442 colistin-resistant (MIC 2 mg/L) Salmonella enterica isolates originating from food producing animals and food products collected since 2011 at the BfR showed, that many isolates (47%) carried the mcr-1 gene. Moreover sequencing of colistin-resistant but mcr-1-negative Salmonella isolates in the frame of the ENGAGE project led to the discovery of the mcr-5 gene in Salmonella. An extended PCR screening for the resistance genes mcr-2 to mcr-5 revealed, that 13% of isolates carried the mcr-4 and 5% the mcr-5 gene. So far, mcr-2 and mcr-3-positive isolates were not detected. The mcr-positive isolates belonged to different Salmonella serovars and were isolated from the primary production (poultry, swine and cattle), as well as food sources (poultry meat and pork). Aim of the study is to extend the PCR screening in Salmonella to novel mcr genes (mcr-6 to mcr-8). Moreover selected isolates are planned to be submitted to whole genome sequencing in order to investigate the distribution of known mcr genes along the food chain. Furthermore sequencing technologies are supposed to be used to investigate novel resistance mechanisms in isolates with unknown cause of colistin resistance. The project is intended to run for two years.
Section overview
Subjects
- Biotechnology
- Food microbiology
- Toxicology
