Connection found between ionophores and antibiotic resistance in people

A new study led by scientists at Carleton University in Ottawa  found a connection between ionophores and antibiotic resistance in people, according to a CIDRAP report.  

Ionophores make up “37% of antibiotics used in food-producing animals on the United States.” They do not appear in human medications. The authors decided to investigate them because “there is increasing concern that ionophore usage could co-select for clinically relevant AMR, since the ionophore resistance genes narA and narB have been found in linkage with multiple AMR genes.”  

They analyzed accessible data regarding genomes with narA and narB genes. The genes were located in “2,442 bacterial isolates from 51 countries, primarily in Enterococcus faecalis and E faecium but also in eight other bacterial species.” More than 20% of the isolates were obtained from humans. This suggests some animal-human transmission, according to the authors.