Salmonella 4,[5],12:i:-, which are currently circulating in swine from the US Midwest, are part of an emerging clade with multidrug-resistant phenotypes and are similar to S typhimuriumfrom Europe, according to the results of recent research published in Clinical Infectious Diseases.
In this study of 659 S 4,[5],12:i:- samples and 325 S typhimurium samples from the United States and Europe, whole genome sequencing was used to evaluate the genetic heterogeneity of the S 4,[5],12:i:- strains from the US Midwest. Resistance genes and other virulence factors were also evaluated in 50 livestock isolates and 22 human isolates.
When S 4,[5],12:i:- isolates from the United States were compared with S typhimurium based on average pairwise single-nucleotide polymorphisms, US S 4,[5],12:i:- were more similar to European S typhimurium than to the US S typhimurium (P <.001).
In an interview with Infectious Disease Advisor, Ehud Elnekave, DVM, PhD, postdoctoral research associate in the Department of Veterinary Population Medicine at the University of Minnesota, explained that “the presence of plasmid-mediated genes, which acquire resistance to important antibiotic classes such as third-generation cephalosporins and fluoroquinolones in Salmonella samples of swine origin, is an important finding, as these can potentially be transmitted to other pathogens.”