The U.S. Centers for Disease Control and Prevention (CDC) recently published a new webpage with information about a persistent, multidrug-resistant strain of Salmonella Infantis known as REPJFX01, which has been the cause of many illnesses and outbreaks.
Persistent strains are those causing illnesses over months or years, despite investigation and prevention efforts. The new webpage includes information about when and where illnesses caused by REPJFX01 have occurred, sources that have been identified, and detailed laboratory data.
Chicken is a significant source associated with foodborne REPJFX01 infections, and REPJFX01 is a leading strain of Salmonella found in chicken produced in the U.S.
According to the new webpage, illness caused by this REPJFX01 was first reported to PulseNet in 2012. As of December 31, 2022, information from 2,900 patients with REPJFX01 infection has been reported to PulseNet. The webpage highlights seven outbreaks of REPJFX01 infections that have been investigated, two of which were linked to chicken.
Whole genome sequencing (WGS) analysis has shown REPJFX01 to be genetically diverse. Bacteria in the strain are within 82 allele differences of one another per core genome multilocus sequence typing (cgMLST). This is more genetically diverse than typical multistate foodborne outbreaks, in which bacteria generally fall within 10 allele differences of one another.
Additionally, isolates from most case patients’ samples have shown resistance to multiple antimicrobials, including several that are recommended for first-line or alternative treatment: ampicillin, ceftriaxone, ciprofloxacin, and trimethoprim-sulfamethoxazole.