Whole genome sequencing reveals antimicrobial resistance determinants (AMR genes) of Salmonella enterica recovered from raw chicken and ready-to-eat leaves imported into England between 2014 and 2019.

Abstract

To compare the antimicrobial resistance (AMR) genes in a genetically diverse group of Salmonella enterica recovered from foods imported into England between 2014 and 2018. Whole genome sequence was used to detect AMR genes or chromosomal mutations associated with AMR in Salmonella recovered from edible leaves imported from Asia (n= 115) as compared to Salmonella (n= 231) isolated from raw chicken, 74% originated from South America. Among isolates from edible leaves, three (3%) showed resistance to at least one antimicrobial agent, two (2%) of which were multidrug resistant (MDR, resistance to three or more antimicrobial classes). Resistance to at least one antimicrobial agent was detected in 214 (93%) in the chicken isolates, with 164 (71%) showing MDR. Genetic diversity and AMR profiles were highly heterogeneous across the different serovars. Resistance was rare among the Salmonella isolates from edible leaves but common (including MDR) among those from raw chicken. Surveillance of AMR in imported foods is essential for monitoring the risk of transmission of resistance from the food chain to humans and provides added public health value to pre-existing controls of the food chain.