...
The CDC has identified REPJFX01 as a persistent, MDR strain of Salmonella Infantis (hereafter referred to as REP Strain) that has led to illnesses and outbreaks both in the US and worldwide. This strain was first documented in PulseNet in 2012. It has spread to individuals in the United States through contaminated chicken and has also been linked to exposures during international travel. The REP strain show resistance to multiple antimicrobials, including key first-line and alternative treatments such as ampicillin, ceftriaxone, ciprofloxacin, and trimethoprim-sulfamethoxazole. Meanwhile, this strain exhibits relatively high genetic diversity, with isolates differing by up to 82 alleles from one another, as determined by cgMLST (core genome multilocus sequence typing). Chen et al. revealed that serovar Infantis is polyphyletic with two lineages identified and one stand-alone singleton that does not cluster with any other Salmonella Infantis isolates. Infantis-A-1-3, a chicken-associated clade estimated to have emerged in 1933, includes a clonal sub-clade which emerged in 1990 and represents 32% of the isolates, with with an increase in the proportion of isolates collected from chicken or chicken-related sources.
...