Curing of a field strain ofSalmonella entericaserovar Infantis isolated from poultry from its highly stable pESI like plasmid

Abstract

AbstractSalmonella entericaserovar Infantis (S. Infantis) is an important emerging pathogen, associated with poultry and poultry products and related to an increasing number of human infections in many countries. A concerning trend amongS. Infantis isolates is the presence of plasmid-mediated multi-drug resistance. In many instances, the genes responsible for this resistance are carried on a megaplasmid known as the plasmid of emergingS. Infantis (pESI) or pESI like plasmids. Plasmids can be remarkably stable due to the presence of multiple replicons and post-segregational killing systems (PSKs), which contribute to their maintenance within bacterial populations. To enhance our understanding ofS. Infantis and its multidrug resistance determinants toward the development of new vaccination strategies, we have devised a method for targeted plasmid curing. This approach effectively overcomes plasmid addiction by leveraging the temporal overproduction of specific antitoxins coupled with the deletion of the partition region. By employing this strategy, we successfully generated a plasmid-free strain from a field isolate derived fromS. Infantis 119944.This method provides valuable tools for studyingS. Infantis and its plasmid-borne multidrug resistance mechanisms.