PurN Is Involved in Antibiotic Tolerance and Virulence in .

can cause chronic infections which are closely related to persister formation. Purine metabolism is involved in persister formation, and , encoding phosphoribosylglycinamide formyltransferase, is an important gene in the purine metabolism process. In this study, we generated a Δ mutant of the Newman strain and assessed its roles in antibiotic tolerance and virulence. The Δ in the late exponential phase had a significant defect in persistence to antibiotics. Complementation of the Δ restored its tolerance to different antibiotics. PurN significantly affected virulence gene expression, hemolytic ability, and biofilm formation in Moreover, the LD (3.28 × 10 CFU/mL) of the Δ for BALB/c mice was significantly higher than that of the parental strain (2.81 × 10 CFU/mL). Transcriptome analysis revealed that 58 genes that were involved in purine metabolism, alanine, aspartate, glutamate metabolism, and 2-oxocarboxylic acid metabolism, etc., were downregulated, while 24 genes involved in ABC transporter and transferase activity were upregulated in Δ vs. parental strain. Protein-protein interaction network showed that there was a close relationship between PurN and GltB, and SaeRS. The study demonstrated that PurN participates in the formation of the late exponential phase persisters via GltB and regulates its virulence by activating the SaeRS two-component system.