Impact of Multiple Antimicrobial Exposures on the Transfer Efficiency of Multidrug Resistance Plasmids in Salmonella enteric

Antimicrobial exposure can potentially lead to increased antimicrobial resistance plasmid transfer. RNA sequencing data was collected from conjugal pairs of Salmonella enterica and Escherichia coli exposed or not exposed to tetracycline over a time course to determine differences in transcript numbers associated with conjugation and tetracycline exposure. The samples were sequenced on the Illumina HiSeq X10 platform with the 150-bp paired-end kit. Among the most highly up-regulated genes in the tetracycline exposed samples were also tetracycline efflux pump genes across the timepoints. In addition, some conjugal transfer-associated genes (e.g. traJ and traA) were upregulated in the tetracycline exposed samples. To assess differential regulation of genes involved in plasmid transfer following tetracycline exposure, we mixed doner (Salmonella enterica 452) and recipient (E. coli J53) and exposed to different concentration of tetracycline. Total RNA was isolated from mating pairs at different time points following tetracycline exposure. A non-tetracycline exposed sample were in parallel with the exposed ones. Three RNA samples were isolates from each time point(triplicate). The differential genes expression during mating experiment following tetracycline were analyzed by comparing it with non-exposed sample for each time points.